Re: Attachment Mod 2.0.1 by Frank H
Just a notion... check to see how php is set for file size limits on your server php configuration file (php.ini), or ask your host. Typical default limit is 2MB. Symptoms when uploading a larger file than allowed are as you describe.
Google: php file size limit ...should give you a good lead.
You can usually get that information from the php info, which I have written about in the documentation for the mod (and in the installation guide). (Every server can have a different setting, that's why I have made a small upload limit in the first place, so you have to figure out what the value is )