the only thing you need to do is creat a phpinfo file
click here to learn how to create a phpinfo file.
once you have your phpinfo file open it with your browser and look for the pcre section:
this is what mine showed:
pcre
| PCRE (Perl Compatible Regular Expressions) Support | enabled |
| PCRE Library Version | 4.5 01-December-2003 |
if you have it disabled, you can edit your php.ini file to enable it.