about control file

[Prasamsa Singh]

Dear Grads user,

I am trying to average 3months data of 3 hourly data set of grided data for a year.
as follows using following control file.

dset ^00%m2%d2.%h2.6.precipitation.bin
options template byteswapped
undef -9999.0
xdef 1440 linear -179.875 0.25000000
ydef 400  linear -49.8750000 0.25000000
zdef 1 levels 1000
tdef 92 linear 00:00Z01jun2000 3hr
* end_time 21:00Z31Aug2000
vars 1
r         0   99 Hourly Rain Rate (mm/hr)
endvars

 I received the result "Entire grid undefined.

 But I could read the data for separate months.
 Would be please suggest me whats wrong in the control file.

Thanking you in advance.

Prasamsa