Another Export Snapshot Problem

[Dave]

Hi,

Anyone got any idea while the following code doesn't work?

     put the windowID of this stack into myWindowID
     put globalLoc(the topLeft of group "GroupCounter") into myFrameRect
     put "," and globalLoc(the bottomRight of group "GroupCounter")  
after myFrameRect
     export snapshot from rect myFrameRect of window myWindowID to  
file myFileName as PNG

When I run it I get an error:

"export no image selected or image not open"

Thanks in advance
All the Best
Dave