Re: Edubuntu 7.04 school guestion
Firstly, Edubuntu 7.04 is ridiculously old. It is not supported anymore and nobody should still be using it. There have been no security patches since 2008. Please move to a later version - 12.04 is a good version and is supported for a while.
To answer your question, you should add write permission to the file it complains about. But really, just upgrade and your problem should disappear anyway.
No idea about your second question.
I try to treat the cause, not the symptom. I avoid the terminal in instructions, unless it's easier or necessary. My instructions will work within the Ubuntu system, instead of breaking or subverting it. Those are the three guarantees to the helpee.