Hi Niko,
I tried Phexample in Squeak and things work great. I had to load in Regex-Core, but that's no biggie. I'll try my hand at editing the ConfigurationOf and send you a patch.
I have only one blip: ForExampleStack >> #shouldFailWhenPopEmpty fails because instead of 'this collection is empty' the example fails with 'this stack is empty'.
I'm not sure how to fix that, given that it's not your problem. One easy way to get a green bar would be to change the error message in Squeak (making it less accurate).
Any thoughts?
frank