Hi John,
I appreciate the data sensitivity issue. You could always take a copy, delete not only the .exe file but also the sqlite.db then zip it and upload it.
There is no reason per se, why you can't have more than 10 text boxes on a form - I have some with upwards of 50 and don't have any problem.
What I have found on occasions is that it will throw an error like the one you're reporting if I've got a form with a lot of fields on it that I've done lots of amendments to (added fields, removed some, renamed them, changed tab sequences etc); it's almost as if internally something has managed to get incorrectly referenced (a totally non-technical explanation - LOL!).
In those events, I've found the best thing to do is to either
1) delete all the fields off the form, re-run the program to see if that 'clears' the problem and start afresh.
2) delete the entire form, re-run the program to see if that 'clears' the problem and start afresh with a replacement form.
It might also be an idea to place fields on the problem form one at a time, run it and, if there is no error, add the next field, run it again and so on. It's a bit tedious (and obviously you wouldn't usually need to do that) but it might help in pinpointing the issue if it still exists.
(The attachment is just to prove that there should be no limit to fields on a form - honest!).
Derek.