unexpected quit on closeStackRequest

[Kurt Kaufman]

The following causes a (repeatable) unexpected quit (according to Mac OS 
X) only when run from within a stack, not as a standalone:

on closeStackRequest
   answer "This will close this application." with "Cancel" or "Close"
   if it is "Cancel" then exit to top
   else
     if there is a file "tempfile.txt" then
       delete file "tempfile.txt"
     end if
      pass closeStackRequest
   end if
end closeStackRequest


Do I perhaps have a line out-of-place?

Thanks, Kurt