hi, if u are using windows 2k3 or 2k, I think I know the problem,
well, it happened to me as well, not in this forum but in my own application I built I'm well known with this error,
the error could appear when you don't have a write/read or the IUSER_ account is not have the permission to the wwwroot or to your application main folder or sub folders that needs to interact with the database file, check if you have a read/write premissions on your main also sub folders!
second the really important thing you should do is to add the user account "Internet Guest Account" (IUSER_) to your application folder and all his sub folder,
My Computer >> go to the folder you want to add the account right click then properties >> security >> add >>
advanced >> find now >> search for the user (IUSER_) >> OK >>
OK >> select the user (IUSER_) and allow him the permissions of:
Modify, Read & Execute, List Folder Contents, Read Write
deny the permission of Full control >> Advanced >>
check the box that says "Replace permission entries on all child objects with entries shown here that apply to child objects" >>
OK >> OK >> that's it!
it should work!
(My recommendation is to do it once on your IIS website directory default site direcotry for the IIS is wwwroot so u won't have a problem with other sites in the future).
Edited by DHiNSaNE