Alright there m8, I had this problem, either. I fixed it with changing my "temporary path directory", because it was running through my windows-folder which was full. This means big mods cannot pass the installation path and consequently not be installed. Go to your setting (general) and change it to a folder which has enough place for any mod you want to activate. Just one thing remains: You habe to start the manager again if you want your result. I hope you'll read it and it'll help you, even if your call for help is a few months old :9 Ps: Sorry fo my bad english im from Germany ;D