While trying to install, it says "command not found" even though I JUST downloaded said package. what could cause that??? I followed the installation instructions to the t once before and everything went great but I wanted to do it again and now I am getting all these "command not found"s. --even though I can use the terminal and browse to the directory where the command is and even see it when I 'ls', it just refuses to run. or sometimes it even happens to my core programs, "vi" for example. Is my ram bad? wtf? I can't get through an installation successfully anymore, what gives.