It looks like either a custom dialog called in the script, or a custom field validation message.
Hi, thanks for that - it worked although I'm not sure what other probs it might have left me. I did have 2 marker fields in cost and job records which had auto-entered values every time a new record was created - I'd forgotten the exact wording of one (and it seemed a bit techy for me!) - and then validation to check what was entered was right both at making a new record and as the job progressed. Presumably the text formatting has changed somewhere, and the validation did not like the entered data, even tho under FM 5.2 it's been doing it for over eight years ! The database's age gives me excuse for forgetting the text I'd used, and hardly ever seen since. I used the Database design report from my copy of FM 5.5 Developer to quickly find the culprits and hopefully all is now well.
Thanks, again, I'll keep you posted if I come across anything else