What is a dr 405 ?

Normally you could press F1 at the input area and get some help. Currently that does not seem to work. Try -1 (Minus 1) which is the universal zero in Lacerte. 

Yes, tried that. Didn’t work 

Florida Personal Property tax return

Then help the client to make a SWAG (Scientific Wild Ass Guess) for the estimate. If Florida thinks it is too far off the mark they will send out an appraiser.
I don't think blank is an appropriate input. Contact support to discuss.