>> I have the number set as descending order
you've got the number as _descending_?
So auto-numbering goes from 2 billion down to 1?
Does the build in Autonumbering even do this? I've never tried descending autonumbering...
Personally I'd have predicted that this is completely unsupported. So it wouldn't surprise me that it fails.
I presume you've set the key to descending because you want to sort a browse with the most recent number forst and you (mistakenly) believe that browses actually make use of keys? (hint: they don't - keys are used for record identification in a database, not sorting.)
If you want the browse to sort a specific way then just set the sort order for the browse to be that way. Don't be hacking the key to do it.
cheers
Bruce