Whilst this error message gives some information it is not that helpful.
But if you get something that indicates a database issue. e.g.
String or binary data would be truncated.
Try running SQL profiler, run a trace and then run your app up to the point of where it fails, checl the profiler timestamps, run the app where it fails, then see in SQL profiler the subsequent trace to find some clues.
The INSERT statement can be cut and pasted into SSMS and run it - then debug that to find the error.
Worked for me....