You probably uploaded the necessary include files and that is why it started working. That sounded like the cause of the issue in the first place, so if you uploaded again and clicked "yes" to include dependent files it would have appeared to automagically work without updating anything.
Can you give me FTP access to the page? I can use that to debug. It could be reserved words as column names, or leaving a blank field value in a column that doesn't allow nulls.
I think there is a setting you can update in the include file to set debug=true and that would give you the full error message, but I'd gladly help you debug if you give me FTP access.