If possible, try updating your copy of Net::Whois::ARIN to the latest version (0.12). By looking at the change log and the module code, it seems that you're running into a bug that was recently fixed:

Revision history for Perl extension Net::Whois::ARIN.
 
0.12    Sat Jun 11 07:52:36 2011
        - fixed point-of-contact parsing bug
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Note the changes made to the contact subroutine of the module source code (lines 393 and 394) to eliminate the possibility of storing data in $records[$n] when $n is -1.