It's good to test your code. At least with -c.

Line 12: A reference is always defined. So the useful code will never be executed.
Line 18: There's a missing { and CGI won't pass under strict subs. And does a return value of undef make most sense?
Line 19: A { should be replaced with (.

Another thought: Wouldn't it be better to check for definedness for every subroutine instead of just the first? What if he decides to define another param subroutine and forget to remove param from @methods? Then the other subroutine won't get defined either. Of course, it would be a lot better to put it in a BEGIN block, as noted. Then you don't have to check for definedness manually, since perl will warn about redefinitions.

ihb