Marten Feldtmann noticed that false is not allowed as a message selector (you get an 'invalid message pattern' error):

http://forum.world.st/false-as-method-name-not-allowed-td4085739.html

It turns out that GemStone generates an error when the special literals (false, true, nil, _remoteNil) are used as message selectors.

This is a bug in in GemStone 2.x and 3.x and should be fixed in a future 3.x release