These project files are duplicates of the wx30 and they have been removed.
If wx3.1 is your default wx, then you can use the wx30 projects and it will work fine.
If not then you'll have to modify the projects (see the custom variables tab) to adjust them to match your setup.
I guess we need to improve our project/workspace setup to allow more flexibility, but this is currently not the case.
If you want to just build a version you want to use the autotools build system is preferable or even building projects.
The cb build system is only useful if you want to develop codeblocks...