Hi Luc--
(I hope you don't mind my including the Spoon and Squeak lists in my response. I think the simulator is of interest in those places.)
I like to play with the interpreter simulator a little more before learning more about Spoon.
What version of VM and image do you use to get InterpreterSimulator up and running? I tried the 3.7.7 VM and 3.7 and 3.8 stock release on linux without success.
I've been using Squeak 3.2 for Spoon (that was the current version when I started in August 2002, and my plan is to move everything from there to a Spoon 1 final system).
As experiment, I followed the guidelines described in http://aspn.activestate.com/ASPN/Mail/Message/squeak/1196663 and http://minnow.cc.gatech.edu/squeak/2465 and got the following trace back
Subscript is out of bounds: 0 Array at: functionPointerFor inClass: addNewMethodToClass internalFindNewMethod commonSend normalSend secondExtendedSendBytecode dispatchOn in: test
So it looks like we've accomplished our annual breaking of the simulator? :) If you decide to give it a go with 3.2, you might also want my simulator fixes[1].
thanks,
-C