You shouldn't use the rc and beta builds.

There's a lot of developement going on and you'll likely experience weird behaviour.

My advice: youse the PBE-image with the 4.0.2 vm.

You can get the image from here: Pharo By Example image

Well, shouldn't is a strong word, we do appreciate reports of issues in RC builds. :)

Going through the PBE as an intro to smalltalk, you'd probably appreciate the calmer waters of using the PBE-image as Max recommended though.

Cheers, 

Henry