I've reviewed this list http://www.modernperlbooks.com/mt/2011/01/how-to-identify-a-good-perl-programmer.html prior to my last couple Perl-related interviews. There is some overlap between the link you provided and chromatic's, but also very good information in both.

Regular Expression in Perl

2. Email id Validation

For me, I'd suggest either they say, "too hard, I'd use Email::Valid" (to be followed up with "Why do you say that?" to see if they actually know why), or "how much validation do you want?" - just as long as they know it's not trivial. Certainly this is a senior vs. junior weeder question, asked this way.

Since I can't see the list:

1. When would yo prefer a hash to an array, and vice versa? Why, in each case?
2. What's your favorite CPAN module? Why? What would you change about it?
3. Do you have any modules on CPAN? What do they do?
4. Explain how objects and inheritance work in Perl.
5. Explain what references do and how they work.
6. When would you prefer a plugin/delegation architecture to an inheritance-base one? Why