capture exception

greeting,

I am not so good at perl/modperl,:)

In the handler, a method from a class was called, when something dies 
from within the method, what's the correct way the handler will take?

for example, I wrote this API which works right if given a correct 
domain name:

http://fenghe.org/domain/?d=yahoo.com

server response:
var data={"registration":"domain may be taken","domain":"yahoo.com"}

If given a wrong domain name:

http://fenghe.org/domain/?d=yahoo.nonexist

The server returns 500.

This is because, in the handler, I used this module (wrote also by me):

http://search.cpan.org/~pyh/Net-Domain-Registration-Check-0.03/lib/Net/Domain/Registration/Check.pm

And in the module, croak like this was happened,

croak "domain TLD not exists" unless tld_exists($tld);

When handler meets the croak, it dies (I guess) and server returns 500.

How will I make the full system work right? fix on handler, or the 
module itself?

Thanks.