Not being able to edit stuff (ie. config files) just blows. If you're *sure* you have vi installed check out some online refs. Actually come to think of it acid_kewpie as a nice link
off his sig that contains a great set of refs. I'd start there, hit the Learning vi link and have at it.
As for your cd try this: 'mount /dev/dcrom' that should mount whatever disk you have in there, so you can 'cd /mnt/cdrom' and get at whatever packages you need.
Hope this helps.