[Inkscape-user] error with gradient mesh - too many heap sessions

Hi Friends, I've just been working on an image testing the gradient mesh. Suddenly out of nowhere (specifically, I was dragging a handle in the mesh, not a node/stop, but handle) a small window popped up with the titlebar "Error in GC" and the message "Too many heap sessions". When I Ok'd that little window, Inkscape closed or crashed. So I can potentially avoid it in the future, what does that mean? And just a general question, while I'm here. It seems the tool is limited to 20 x 20 rows and columns. Or is there some way to get more?

Thanks for your help :-)