Virtualbox Guest Additions (again)

[zabyss]

First, I have to apologize. I've been searching and there are several threads on this topic, but none are helping. I'm completely new to Linux and there is a learning curve. I already posted this on another thread (http://ubuntuforums.org/showthread.php?t=400205) but I didn't think it would get as much traffic. Essentially I'm having the same problem that the individual in this thread (http://ubuntuforums.org/showthread.php?t=402186).

I have a installed Ubuntu Studio 7.04 via Virtualbox on my Windows XP laptop. I'm stuck at the 1024x768 resolution which I find extremely counterproductive. This isn't 1995 after all... I need to install the guest additions, but I'm having trouble. I've got the .iso mounted, and it shows on the Ubuntu desktop. I can't open the files or get it running in any way. I tried the commands suggested in the aforementioned thread (http://ubuntuforums.org/showthread.php?t=402186) but to no avail. It keeps telling me it cannot open the file. I did once get it to prompt me for my password but it said the same thing, and now I can't get that even. I know I'm doing something wrong here because I don't know how Linux works. I really kinda need this spelled out.

Can anyone give me a hand? I would really appreciate it!