[gembud] Problem with gd_rdat

I'm and "old" GEMPAK user and have used subroutine gd_rdat to read GEMPAK
grids for a long time with generally no problems.
Now, not matter what I try, when I read a GEMPAK vertical motion grid
("OMEG", in pressure difference layer-PDLY. 180 to 150 mb) it returns with
NO error, but the majority of the grid returned is very small numbers like
-2.xxxx E -08.
The GEMPAK grid displays the correct data when I plot it and in GDLIST, the
number also look fine, but I cannot figure out where these "random" bad
numbers are coming from.
I've checked for usual FORTRAN errors and found nothing.
Thanks
Phillip