anygui newbie question

[Gerard C Blais]

I'm trying to learn anygui, running on Win98.  When I run backend(), I
get mswgui.

I've typed in the first program from the manual (one button, random
sentence in text box  on click).

Window comes up fine.  When I click the button, I get a run-time error
and the traceback says my handler function has received an unexpected
argument, "source".  As far as I can tell, "source" should be
expected.

I do have a link call (link (btn, handler).

Any ideas?  Any place to look besides the on-line manual ahd Hetland's
Practical Python?

Thanks,

Gerry