Undefined subroutine &__PACAKGE__::bar called

First of all you misspelled PACKAGE, which is not a good thing to do.

But the real reason is that __PACKAGE__ is only handled specially when it's a term on it own, not when it's part of a name.

And finally __PACKAGE__ as a separate term becomes a string, and you can't write "MyPackage"::bar() either.