Fatal error class.mysql.driver.php on line 58

Golovinks

Hi all,
I am in the vanilla version 2 installer page, and i have filled all the information required by the setup page, and i am getting this error:
Fatal error: Call to undefined function ctype_alnum() in /library/database/class.mysql.driver.php on line 58

UnderDog

Check your PHP version towards the minimum requirements.
See all the links in this search result:
http://www.google.com/search?q=Call+to+undefined+function+ctype_alnum&hl=en&newwindow=1&num=100&lr=&ft=i&cr=&safe=images&tbs=
And another link (I like the forum of this link)
http://flatpress.org/vanilla2/discussion/483/fatal-error-call-to-undefined-function-ctype_alnum-in-homechegregorcypublic_htmlafflatp/p1
and a little quote:
ctype_alnum can be substituted by preg_match('/^[a-zA-Z0-9]+$/', $string)