Re: "Could not open lock file" - help, I don't understand!
That means that you have more than one package manager open at a time. Close the other one down and try again.
EDIT: MAybe more info is needed. Whenever you download or update a package the package manager 'locks' a file that prevents and other new packages from being accessed. You you just have to close the other think that is touching the packages before it will release the lock and let you download what you want.
"What gets us into trouble is not what we don't know, it's what we know for sure that just ain't so." - Mark Twain