InfoPath Dev

I created this InfoPath form that is linked to SharePoint. The form works great and is usually succesful but once in awhile, if there are too many characters/words on this one text box, It gives me an error message (with no details??). I can put as many words/characters in every other text box, its just...

Background I have a browser-enabled InfoPath form, with a data connection to a SharePoint list. Upon loading, it pulls in data from the SP list and populates a load of fields. It worked fine in development, and it worked fine when there were a few rows of data in the list when I deployed the form. However...