modules and gui

I had a brief try last night to get my module to start a wimp session, when I tried I got an Internal error…bla bla.
I didn’t have time to debug it, but I’ve seen that AcornURI is a module AND starts a wimptask.
Is there anything special I should be doing, such as setting some kind of mode.
I’m figuring not and it’s a code fault, but it wasn’t immediately obvious.

Not claiming Service_Memory is the likely cause