Convolution hang!

When I use glConvolutionFilter2DEXT() in my Wildcat 5110, It hang my computer after serval times window refresh. And I cant see the correct result in the window. I dont know why? Can anybody give my a simple demo to test it?

try here

Thank you very much!
After I ran the “GLAF”, My program became
ok !! It seems very strange! But I dont know
the reason.