When CPAN downloads a package, it fetches a .gz file in exactly the manner described in the first response.   It is possible to do, by hand, everything that CPAN conveniently automates.   If you, as you did, accidentally mung a package upon which CPAN depends, you need to fix the problem by hand.   CPAN is “very convenient, but not magickal.”

You can also, of course, reinstall CPAN ... as though you were doing so for the first time.   This will bring in all of the packages upon which CPAN depends.   Then, you simply upgrade CPAN to bring everything up-to-date.   However, since you know exactly what the missing dependency is (and if you are reasonably sure that you did not blast-away something else...), a spot replacement of just this one package should be sufficient.   (If it is not, then you’ll know soon enough.)

Either way, while you might need to make a pit-stop at the PM Confessional thread over in “Meditations,” this situation is actually just an annoyance, and maybe even a good exercise in practical firefighting.   You are not, actually, “scro-o-o-ooed.”