Bad Request

Please give me a solution to fix this problem. I am able to logon to other websites successfully. When I logon to www.gmatclub.com, I get the following message: -

Bad Request
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.

Cookie: phpbb2mysql_4910_uf=1085560320; phpbb2mysql_4910_u=a%3A194%3A%7Bi%3A6734%3Bi%3A0%3Bi%3A6747%3Bi%3A0%3Bi%3A6696%3Bi%3A0%3Bi%3A6484%3Bi%3A0%3Bi%3A6614%3Bi%3A0%3Bi%3A6720%3Bi%3A0%3Bi%3A6702%3Bi%3A0%3Bi%3A6710%3Bi%3A0%3Bi%3A6712%3Bi%3A0%3Bi%3A6764%3Bi%3A0%3Bi%3A6757%3Bi%3A0%3Bi%3A6749%3Bi%3A0%3Bi%3A6771%3Bi%3A0%3Bi%3A6434%3Bi%3A0%3Bi%3A6770%3Bi%3A0%3Bi%3A6761%3Bi%3A0%3Bi%3A6758%3Bi%3A0%3Bi%3A6814%3Bi%3A31345%3Bi%3A6813%3Bi%3A31345%3Bi%3A6797%3Bi%3A31345%3Bi%3A6815%3Bi%3A31345%3Bi%3A6796%3Bi%3A31345%3Bi%3A6798%3Bi%3A31345%3Bi%3A6812%3Bi%3A31345%3Bi%3A6800%3Bi%3A31345%3Bi%3A6799%3Bi%3A31345%3Bi%3A6810%3Bi%3A31345%3Bi%3A6811%3Bi%3A31345%3Bi%3A6809%3Bi%3A31345%3Bi%3A6792%3Bi%3A31345%3Bi%3A6784%3Bi%3A31345%3Bi%3A6785%3Bi%3A31345%3Bi%3A6786%3Bi%3A31345%3Bi%3A6783%3Bi%3A31345%3Bi%3A6782%3Bi%3A31345%3Bi%3A6779%3Bi%3A31345%3Bi%3A6780%3Bi%3A31345%3Bi%3A6787%3Bi%3A31345%3Bi%3A6788%3Bi%3A31345%3Bi%3A6793%3Bi%3A31345%3Bi%3A6794%3Bi%3A31345%3Bi%3A6816%3Bi%3A31345%3Bi%3A6791%3Bi%3A31345%3Bi%3A6789%3Bi%3A31345%3Bi%3A6790%3Bi%3A31345%3Bi%3A6795%3Bi%3A31345%3Bi%3A6817%3Bi%3A31345%3Bi%3A6848%3Bi%3A31345%3Bi%3A6849%3Bi%3A31345%3Bi%3A6850%3Bi%3A31345%3Bi%3A6851%3Bi%3A31345%3Bi%3A6847%3Bi%3A31345%3Bi%3A6846%3Bi%3A31345%3Bi%3A6842%3Bi%3A31345%3Bi%3A6843%3Bi%3A31345%3Bi%3A6853%3Bi%3A31345%3Bi%3A6845%3Bi%3A31345%3Bi%3A6852%3Bi%3A31345%3Bi%3A6860%3Bi%3A31345%3Bi%3A6861%3Bi%3A31345%3Bi%3A6862%3Bi%3A31345%3Bi%3A6863%3Bi%3A31345%3Bi%3A6864%3Bi%3A31345%3Bi%3A6859%3Bi%3A31345%3Bi%3A6858%3Bi%3A31345%3Bi%3A6855%3Bi%3A31345%3Bi%3A6856%3Bi%3A31345%3Bi%3A6857%3Bi%3A31345%3Bi%3A6841%3Bi%3A31345%3Bi%3A6839%3Bi%3A31345%3Bi%3A6824%3Bi%3A31345%3Bi%3A6825%3Bi%3A31345%3Bi%3A6826%3Bi%3A31345%3Bi%3A6827%3Bi%3A31345%3Bi%3A6823%3Bi%3A31345%3Bi%3A6822%3Bi%3A31345%3Bi%3A6818%3Bi%3A31345%3Bi%3A6819%3Bi%3A31345%3Bi%3A6820%3Bi%3A31345%3Bi%3A6821%3Bi%3A31345%3Bi%3A6828%3Bi%3A31345%3Bi%3A6829%3Bi%3A31345%3Bi%3A6835%3Bi%3A31345%3Bi%3A6836%3Bi%3A31345%3Bi%3A6837%3Bi%3A31345%3Bi%3A6838%3Bi%3A31345%3Bi%3A6834%3Bi%3A31345%3Bi%3A6833%3Bi%3A31345%3Bi%3A6830%3Bi%3A31345%3Bi%3A6831%3Bi%3A31345%3Bi%3A6832%3Bi%3A31345%3Bi%3A6778%3Bi%3A31345%3Bi%3A6781%3Bi%3A31345%3Bi%3A6801%3Bi%3A31345%3Bi%3A6476%3Bi%3A31345%3Bi%3A6694%3Bi%3A31345%3Bi%3A6695%3Bi%3A31345%3Bi%3A6703%3Bi%3A31345%3Bi%3A6700%3Bi%3A31345%3Bi%3A6371%3Bi%3A31345%3Bi%3A5890%3Bi%3A31345%3Bi%3A4763%3Bi%3A31345%3Bi%3A6777%3Bi%3A31345%3Bi%3A5343%3Bi%3A31345%3Bi%3A5410%3Bi%3A31345%3Bi%3A5680%3Bi%3A31345%3Bi%3A5600%3Bi%3A31345%3Bi%3A6714%3Bi%3A31345%3Bi%3A5596%3Bi%3A31345%3Bi%3A6765%3Bi%3A31345%3Bi%3A6762%3Bi%3A31345%3Bi%3A6756%3Bi%3A31345%3Bi%3A6772%3Bi%3A31345%3Bi%3A6774%3Bi%3A31345%3Bi%3A6776%3Bi%3A31345%3Bi%3A6715%3Bi%3A31345%3Bi%3A6752%3Bi%3A31345%3Bi%3A6773%3Bi%3A31345%3Bi%3A6724%3Bi%3A31345%3Bi%3A6732%3Bi%3A31345%3Bi%3A6726%3Bi%3A31345%3Bi%3A6721%3Bi%3A31345%3Bi%3A6888%3Bi%3A527881%3Bi%3A2167%3Bi%3A527881%3Bi%3A6902%3Bi%3A527881%3Bi%3A6904%3Bi%3A527881%3Bi%3A6901%3Bi%3A527881%3Bi%3A2273%3Bi%3A527881%3Bi%3A6894%3Bi%3A527881%3Bi%3A6869%3Bi%3A527881%3Bi%3A6903%3Bi%3A527881%3Bi%3A6899%3Bi%3A527881%3Bi%3A6920%3Bi%3A614814%3Bi%3A6919%3Bi%3A614814%3Bi%3A6918%3Bi%3A614814%3Bi%3A6917%3Bi%3A614814%3Bi%3A6886%3Bi%3A614814%3Bi%3A6906%3Bi%3A614814%3Bi%3A6916%3Bi%3A614814%3Bi%3A6645%3Bi%3A614814%3Bi%3A6914%3Bi%3A614814%3Bi%3A6915%3Bi%3A614814%3Bi%3A6927%3Bi%3A636924%3Bi%3A6924%3Bi%3A636924%3Bi%3A5363%3Bi%3A636924%3Bi%3A5686%3Bi%3A636924%3Bi%3A6497%3Bi%3A636924%3Bi%3A6925%3Bi%3A636924%3Bi%3A6926%3Bi%3A636924%3Bi%3A6923%3Bi%3A636924%3Bi%3A6932%3Bi%3A636924%3Bi%3A6931%3Bi%3A636924%3Bi%3A6930%3Bi%3A636924%3Bi%3A6929%3Bi%3A636924%3Bi%3A6933%3Bi%3A636924%3Bi%3A6943%3Bi%3A697065%3Bi%3A6935%3Bi%3A697065%3Bi%3A6936%3Bi%3A697065%3Bi%3A6938%3Bi%3A697065%3Bi%3A6934%3Bi%3A697065%3Bi%3A6939%3Bi%3A697065%3Bi%3A6937%3Bi%3A697065%3Bi%3A6948%3Bi%3A719853%3Bi%3A6949%3Bi%3A719853%3Bi%3A6950%3Bi%3A719853%3Bi%3A6956%3Bi%3A719853%3Bi%3A6947%3Bi%3A719853%3Bi%3A6945%3Bi%3A719853%3Bi%3A5528%3Bi%3A719853%3Bi%3A6574%3Bi%3A719853%3Bi%3A6952%3Bi%3A719853%3Bi%3A6944%3Bi%3A719853%3Bi%3A6946%3Bi%3A719853%3Bi%3A6951%3Bi%3A719853%3Bi%3A6892%3Bi%3A719853%3Bi%3A6958%3Bi%3A719853%3Bi%3A6957%3Bi%3A719853%3Bi%3A6955%3Bi%3A719853%3Bi%3A6953%3Bi%3A719853%3Bi%3A6954%3Bi%3A719853%3Bi%3A6976%3Bi%3A762029%3Bi%3A6905%3Bi%3A762029%3Bi%3A6975%3Bi%3A762029%3Bi%3A6962%3Bi%3A762029%3Bi%3A6969%3Bi%3A788371%3Bi%3A6964%3Bi%3A788371%3Bi%3A6981%3Bi%3A793547%3Bi%3A6960%3Bi%3A793547%3Bi%3A6968%3Bi%3A793547%3Bi%3A6974%3Bi%3A793547%3Bi%3A6972%3Bi%3A793547%3Bi%3A6963%3Bi%3A793547%3Bi%3A6961%3Bi%3A793547%3Bi%3A6921%3Bi%3A793547%3B%7D; phpbb2mysql___lastvisit=1086225570; phpbb2mysql___uf=0; phpbb2mysql___u=a%3A0%3A%7B%7D; phpbb2mysql_5623_uf=1085375993; phpbb2mysql_5623_u=a%3A178%3A%7Bi%3A6794%3Bi%3A0%3Bi%3A6795%3Bi%3A0%3Bi%3A6796%3Bi%3A0%3Bi%3A6797%3Bi%3A0%3Bi%3A6793%3Bi%3A0%3Bi%3A6792%3Bi%3A0%3Bi%3A6788%3Bi%3A0%3Bi%3A6789%3Bi%3A0%3Bi%3A6790%3Bi%3A0%3Bi%3A6791%3Bi%3A0%3Bi%3A6798%3Bi%3A0%3Bi%3A6799%3Bi%3A0%3Bi%3A6813%3Bi%3A0%3Bi%3A6814%3Bi%3A0%3Bi%3A6815%3Bi%3A0%3Bi%3A6816%3Bi%3A0%3Bi%3A6812%3Bi%3A0%3Bi%3A6811%3Bi%3A0%3Bi%3A6800%3Bi%3A0%3Bi%3A6809%3Bi%3A0%3Bi%3A6810%3Bi%3A0%3Bi%3A6787%3Bi%3A0%3Bi%3A6786%3Bi%3A0%3Bi%3A6771%3Bi%3A0%3Bi%3A6772%3Bi%3A0%3Bi%3A6773%3Bi%3A0%3Bi%3A6774%3Bi%3A0%3Bi%3A6770%3Bi%3A0%3Bi%3A6766%3Bi%3A0%3Bi%3A6762%3Bi%3A0%3Bi%3A6763%3Bi%3A0%3Bi%3A6765%3Bi%3A0%3Bi%3A6775%3Bi%3A0%3Bi%3A6776%3Bi%3A0%3Bi%3A6782%3Bi%3A0%3Bi%3A6783%3Bi%3A0%3Bi%3A6784%3Bi%3A0%3Bi%3A6785%3Bi%3A0%3Bi%3A6781%3Bi%3A0%3Bi%3A6780%3Bi%3A0%3Bi%3A6777%3Bi%3A0%3Bi%3A6778%3Bi%3A0%3Bi%3A6779%3Bi%3A0%3Bi%3A6817%3Bi%3A0%3Bi%3A6818%3Bi%3A0%3Bi%3A6848%3Bi%3A0%3Bi%3A6849%3Bi%3A0%3Bi%3A6850%3Bi%3A0%3Bi%3A6851%3Bi%3A0%3Bi%3A6847%3Bi%3A0%3Bi%3A6846%3Bi%3A0%3Bi%3A6842%3Bi%3A0%3Bi%3A6843%3Bi%3A0%3Bi%3A6853%3Bi%3A0%3Bi%3A6845%3Bi%3A0%3Bi%3A6852%3Bi%3A0%3Bi%3A6860%3Bi%3A0%3Bi%3A6861%3Bi%3A0%3Bi%3A6862%3Bi%3A0%3Bi%3A6863%3Bi%3A0%3Bi%3A6864%3Bi%3A0%3Bi%3A6859%3Bi%3A0%3Bi%3A6858%3Bi%3A0%3Bi%3A6855%3Bi%3A0%3Bi%3A6856%3Bi%3A0%3Bi%3A6857%3Bi%3A0%3Bi%3A6841%3Bi%3A0%3Bi%3A6839%3Bi%3A0%3Bi%3A6824%3Bi%3A0%3Bi%3A6825%3Bi%3A0%3Bi%3A6826%3Bi%3A0%3Bi%3A6827%3Bi%3A0%3Bi%3A6823%3Bi%3A0%3Bi%3A6822%3Bi%3A0%3Bi%3A6819%3Bi%3A0%3Bi%3A6820%3Bi%3A0%3Bi%3A6821%3Bi%3A0%3Bi%3A6828%3Bi%3A0%3Bi%3A6829%3Bi%3A0%3Bi%3A6835%3Bi%3A0%3Bi%3A6836%3Bi%3A0%3Bi%3A6837%3Bi%3A0%3Bi%3A6838%3Bi%3A0%3Bi%3A6834%3Bi%3A0%3Bi%3A6833%3Bi%3A0%3Bi%3A6830%3Bi%3A0%3Bi%3A6831%3Bi%3A0%3Bi%3A6832%3Bi%3A0%3Bi%3A6761%3Bi%3A0%3Bi%3A6760%3Bi%3A0%3Bi%3A6686%3Bi%3A0%3Bi%3A6688%3Bi%3A0%3Bi%3A6691%3Bi%3A0%3Bi%3A6693%3Bi%3A0%3Bi%3A6652%3Bi%3A0%3Bi%3A6764%3Bi%3A0%3Bi%3A6588%3Bi%3A0%3Bi%3A6594%3Bi%3A0%3Bi%3A6610%3Bi%3A0%3Bi%3A6614%3Bi%3A0%3Bi%3A6694%3Bi%3A0%3Bi%3A6695%3Bi%3A0%3Bi%3A6703%3Bi%3A0%3Bi%3A6705%3Bi%3A0%3Bi%3A6710%3Bi%3A0%3Bi%3A6711%3Bi%3A0%3Bi%3A6702%3Bi%3A0%3Bi%3A6700%3Bi%3A0%3Bi%3A6696%3Bi%3A0%3Bi%3A6698%3Bi%3A0%3Bi%3A6699%3Bi%3A0%3Bi%3A6801%3Bi%3A0%3Bi%3A6576%3Bi%3A0%3Bi%3A5410%3Bi%3A0%3Bi%3A5596%3Bi%3A0%3Bi%3A5600%3Bi%3A0%3Bi%3A5629%3Bi%3A0%3Bi%3A5343%3Bi%3A0%3Bi%3A4858%3Bi%3A0%3Bi%3A1817%3Bi%3A0%3Bi%3A4763%3Bi%3A0%3Bi%3A4856%3Bi%3A0%3Bi%3A5660%3Bi%3A0%3Bi%3A5680%3Bi%3A0%3Bi%3A6476%3Bi%3A0%3Bi%3A6484%3Bi%3A0%3Bi%3A6560%3Bi%3A0%3Bi%3A6568%3Bi%3A0%3Bi%3A6434%3Bi%3A0%3Bi%3A6371%3Bi%3A0%3Bi%3A5825%3Bi%3A0%3Bi%3A5890%3Bi%3A0%3Bi%3A5923%3Bi%3A0%3Bi%3A6712%3Bi%3A0%3Bi%3A6713%3Bi%3A0%3Bi%3A6744%3Bi%3A0%3Bi%3A6745%3Bi%3A0%3Bi%3A6746%3Bi%3A0%3Bi%3A6747%3Bi%3A0%3Bi%3A6743%3Bi%3A0%3Bi%3A6742%3Bi%3A0%3Bi%3A6739%3Bi%3A0%3Bi%3A6740%3Bi%3A0%3Bi%3A6741%3Bi%3A0%3Bi%3A6748%3Bi%3A0%3Bi%3A6749%3Bi%3A0%3Bi%3A6756%3Bi%3A0%3Bi%3A6757%3Bi%3A0%3Bi%3A6758%3Bi%3A0%3Bi%3A6759%3Bi%3A0%3Bi%3A6755%3Bi%3A0%3Bi%3A6754%3Bi%3A0%3Bi%3A6750%3Bi%3A0%3Bi%3A6752%3Bi%3A0%3Bi%3A6753%3Bi%3A0%3Bi%3A6738%3Bi%3A0%3Bi%3A6737%3Bi%3A0%3Bi%3A6720%3Bi%3A0%3Bi%3A6721%3Bi%3A0%3Bi%3A6722%3Bi%3A0%3Bi%3A6723%3Bi%3A0%3Bi%3A6719%3Bi%3A0%3Bi%3A6717%3Bi%3A0%3Bi%3A6714%3Bi%3A0%3Bi%3A6715%3Bi%3A0%3Bi%3A6716%3Bi%3A0%3Bi%3A6724%3Bi%3A0%3Bi%3A6725%3Bi%3A0%3Bi%3A6732%3Bi%3A0%3Bi%3A6733%3Bi%3A0%3Bi%3A6734%3Bi%3A0%3Bi%3A6736%3Bi%3A0%3Bi%3A6731%3Bi%3A0%3Bi%3A6730%3Bi%3A0%3Bi%3A6726%3Bi%3A0%3Bi%3A6728%3Bi%3A0%3Bi%3A6729%3Bi%3A0%3Bi%3A4683%3Bi%3A0%3B%7D; phpbb2mysql_data=a%3A2%3A%7Bs%3A11%3A%22autologinid%22%3Bs%3A32%3A%22f9fd0b6dd186c9a43f5944cc4a95cfac%22%3Bs%

----------------
Mayur