Opening and saving existing document results in "Field in note has wrong datatype" error

I have a problem in my db which I cant work out …

Users can create new documents, but if they then open them in edit mode and save (whether or not they make any changes) a “Field in note has wrong datatype” error.

I dont understand how this can occur - I can create a document and edit it seconds later (ie no changes have been made to the design in this time) and still get the error.

I also dont know how to even isolate which field is causing the problem, as I cant seem to get an error message that is more explicit than the one above.

I’d appreciate anyones suggestions/help as I’m really stuck on this one.

Gail

ps Ive tried DB fixup, and compact as copy just in case but these didn’t make a difference.