[gradsusr] Plot GFS grib2 files

[claudiomet]

Hi users!

I'm dowlloading grib2 files GFS outputs from
http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.xxxxxxxxxx/gfs.txxz.pgrb2bfxx
(and idx file too)
I have instaled las version of GrADS (2.0.a9), last version of wgrib2
(1.9.4) and last g2ctl script

I made:
g2ctl gfs.txxz.pgrb2bfxx > gfs.txxz.pgrb2bfxx.ctl
and ctl file are correctly crated, then I made:
gribmap -i gfs.txxz.pgrb2bfxx.ctl
to update the idx file, then I have 3 files (grib2 file, ctl file and idx file)

I open grads, I load the file, and the file loads correctly,
but when I want to display any variable (set lev 500 > set HGTprs for
example) grads says

"Cannot contour grid - all undefines values"

What can be the problem ?
Thanks!
-- 
Claudio Cortes