When booting VIM: Errors E121: Undefined variable: VundleInstalled & E15: Invalid expression: VundleInstalled == 1

Hmm, that is odd. You might try updating your vundle install

$ cd ~/.vim/bundle/vundle.vim
$ git pull

You could also try grepping for that variable in your bundles:

$ cd ~/.vim/bundle
$ grep VundelInstalled

Give those a shot and see if they help clear things up.