Thanks Chad, I'm actually happy to know that this is something that you be able to eventually fix on your end.
I actually went ahead and rebuilt the page from backup data that I had (although it was tedious!), but I will experiment with your suggestions just in case it happens again.
In my situation, what caused the problem was a bad SQL statement, where I had a select statement that joined several tables together... and I neglected to explicitly give the full name of a field which was named the same in two tables... so an ambiguous reference...
Patrick