Thanks Terry, you are correct there was no unique key set for the description, the other fields with lookup had it.
However, I altered the dictionary, created a unique index, re compiled and I still get the error.
I also deleted the field off the form, saved the app re-generated.
edited the form put the auto lookup back and still get the same error ?
I am sure that what you suggested was the correct fix, but I think something in the generator is still wrong , any suggestions ?