Here are some load scripts to load MetacelloBrowser <http://metacellobrowser.dcc.uchile.cl/> and at least open it up in a fresh Squeak 4.2 11042
I do not know if it is working properly or not. If anyone has better load scripts, please let us know.

When loading Grease I get this missing dependency error a few times: 
This package depends on the following classes:
  ParseTreeEnvironment
  RBTransformationRule
  RBBlockLintRule
  RBParseTreeLintRule

I don't know where to get the missing stuff from at the moment or whether it would work in Squeak.

I just clicked Proceed each time the error came up.

Do each section by itself in a Workspace.

"=================================="
"Gofer"
"Gofer is at 'http://source.lukas-renggli.ch/gofer', "
"Gofer docs reside at http://www.lukas-renggli.ch/blog/gofer" 

(Installer repository: 'http://source.lukas-renggli.ch/gofer/')
	install: 'Gofer';
	install: 'Gofer-Core';
	install: 'Gofer-Tests';
yourself. 

"=================================="
"Grease"
(Installer repository: 'http://www.squeaksource.com/Seaside30/')
	install: 'Grease-Core';
	install: 'Grease-Slime';
	install: 'Grease-Tests-Core';
	install: 'Grease-Tests-Slime';
	install: 'ConfigurationOfGrease';
yourself. 

"==================================="
"MetacelloBrowser"
"http://metacellobrowser.dcc.uchile.cl/"

Gofer new
	squeaksource: 'MetacelloBrowser'; 
	package: 'ConfigurationOfMetacelloBrowser';
	load.
((Smalltalk at: #ConfigurationOfMetacelloBrowser) project perform: #lastVersion) load.

"==================================="
MetacelloBrowser open. 

For your enjoyment,
Ken G. Brown