Here's how I got the Generic Function code
running starting with a clean image.
(Please use an expendible image if you
experiment with the code.)

File in:

ADVANCED install.st (take everything)
EVENTS events.st
The entire Refactoring Browser
John's MethodWrapper.st, Synchronization,
Interaction, and Coverage files.

From this directory:

Method-Wrappers.st (slight changes from Brant, may not be needed)
Generic-Functions.st
generic.st
MultiMethod-Menagerie.st

That <should do it>

Be aware that this is very new, experimental code,
and you should have no difficulty breaking it.

To run a GF:

Go to MultiMethod-Menagerie>>ethology|Mouse>>moveThrough:<Land>
"Do" the line that makes the GF's 
MethodCombination be SubStandardMethodCombination
"Do" the line that sends a Land to a Mouse.