Well in regards to the next button only dialog. That is because at that point in the installer the program is installed. So there is no going back without running the uninstaller. Sorry that is just the nature of INNO Setup.
It makes sense to me because all of the installation tasks are already done at that point I just display the change log at that time which is for your benefit. 'Next' is all there is left to do in the installer. Sorry that you want to quite at that point, but doing that now doesn't have any effect on the installer.
So in other words, it has already put all it information and files on to your system. In fact I believe you killing the installer at that point leaves the temporary files on your system without properly cleaning them up. I think that is causing your problem. It needs to get rid of the partial wxAdditions install that it downloaded. It does this as the last step. So please try to finish the installer out and that way a fresh copy from the web server can be downloaded after running the installer again. You can also just delete all the files in your temp folder too. In fact, you should find a file named
wxAdditions_setup.exe in your temp folder if my thinking about file clean up is correct. On a completed setup this would NOT be there.
Can we move this discussion over to the wxFormBuilder Forum.
That way we aren't taking up Code::Blocks forum. Thanks