Did you get the exact same error as originally reported? If so, then send me the sqlite data file so I can look for data integrity issues.
If you got a different error, give me the full details, including at what point in the upgrade it occurred.
If the data was successfully migrated to the SQL CE database, the fix could be as simple as tweaking the web.config file to point to the new data provider. The Admin Guide describes tools you can use to look inside the .sdf database.
Roger Martin
Creator and Lead Developer of Gallery Server Pro