correlation between index and SST

[hgiap]

And I have one index serials,and key-index.dat,index.ctl,this is one
dimension
now I want to see the correlation between the index and sst data,
and my *.gs as follow:
reinit
open index.ctl
open sst678.ctl
enable print corr-sst.gmf
set grads off
set x 1
set y 1
set t 1 45
define kk=aave(A,lon=-120,lon=240,lat=-35,lat=50)
set lon -120 240
set lat -35 50
set t 1
set gxout shaded
d tcorr(kk,sst.2,t=1,t=45)

BUT ALSO SHOW:
DATA request error:Invalid grid coordinates
world coordinates convert to non-integer grid
......