execution inside of Perl reg ex?

[Cypher <cypher () EXECPC COM>]

hello -

I have a question relating to executing code inside of a Win32 Perl
regular expression. I am trying to find a vulnerability in a CGI program
of unknown origin named search.pl (to which I, unfortunately, do not have
the source).  The CGI does not do any error checking on input characters
which are, presumably, passed into a reg ex. For example, when I input:

(?{print"hello";})

or anything else in (?{...}) format, I get the following error:

CGI Error
The specified CGI application misbehaved by not returning a complete set
of HTTP headers. The headers it did return are:

/(?{print"hello";})/: Eval-group not allowed at runtime, use re 'eval' at
D:\Inetpub\cgi-bin\search.pl line 261.


My question is, does anyone know of any other ways to execute code in a
reg ex?  Or, and this is an even longer shot, is there anyway of fooling
Perl into ignoring the fact that use re 'eval' has not been specified?
Also, the program must split on a space, since inputting

(?{print "hello";})

causes search.pl to return the following error:

/(?{print/: Sequence (?{...}) not terminated or not {}-balanced at
D:\Inetpub\cgi-bin\search.pl line 261


Any ideas? Also, does anyone know of any good Perl hacking/security pages?
I have searched quite a bit, but have not been able to find anything
useful. thanks -

        /d