someone please help, I cannot get passed nan to nan interval error

[David Szenasi]

I am running GRaDS 1.8 on a linux redhat system.  I was able to get output
from my binary data file and printed some contour plots for a seven day
period.  I then typed the command "set t 1 366" and then "d p", p is
precipitation.  It ran through the time periods and then stopped.  I
then "set t 25" for example and recieved the error "nan to nan interval
inf".  I reinit GRaDS and tried other data files.  I have also restarted
GRaDS multiple times and still recieve this error for every time in the
data set except those that I had already displayed.  I've been tring for
days to overcome this problem, please help.

David Szenasi
UNM