Repairing a corrupt sqlite database.

I have been having some nagging problems, and I'm pretty sure my database is mangled.  Sometimes I can't access my forum at all, and after some minutes I get "can't access user table."  I can no longer use "show posts since last visit" because I get "unable to delete search results"

on my own box, I have successfully converted the database to mysql, and in the process of converting I found out that there are duplicate entries and things like that.  I have not been successful in converting on the server where my forum is hosted--it does run a different distro, so that may have something to do with it, but regardless,

1.  is there some way for me to reliably repair my db?
2.  can I use sqlite3 yet?