Try this it worked for me when one of our users had this
problem, I use Vista with Contribute CS3.
Ensure Contribute is closed before following these steps:
1 - Open windows explorer or My Computer
2 - Check hidden files and folders are visible (Tools >
View tab > Show hidden files and folders)
3 - navigate to C:\Documents and Settings\<user
(where <user name> = user's folder)
4 - rename the Configuration file to something like
5 - open contribute and check if the error has disappeared.
Contribute will rebuild the configuration file if you rename
it before opening contribute and this usually fixes any corrupt
data in there.