SQL vulnerability

SQL injection vulnerability in downloadcrew.com
Errors are put as comments in the HTML

Example of vulnerable pages:
http://downloadcrew.com/?act=search&cat='30


<!--
	PDOException - SQLSTATE[22P02]: Invalid text representation: 7 ERROR:  invalid input syntax for integer: &quot;&quot; or &quot;&quot; = &quot;&quot;<p>SELECT * FROM categories WHERE id = :id<br />
Array<br />
(<br />
)<br />


	Stack trace:
	#0 /home/n/q/nqdownloadcrew/web/public_html/classes/class.db.connection.php(123): PDOStatement-&gt;execute()<br />
#1 /home/n/q/nqdownloadcrew/web/public_html/classes/views/view.php(117): DBStatement-&gt;execute()<br />
#2 /home/n/q/nqdownloadcrew/web/public_html/classes/views/category.php(47): View-&gt;LoadByStmt(Object(DBStatement))<br />
#3 /home/n/q/nqdownloadcrew/web/public_html/actions/search.php(73): ViewCategory::LoadByID(Object(DBConnection), '&quot; or &quot;&quot; = &quot;')<br />
#4 /home/n/q/nqdownloadcrew/web/public_html/index.php(115): require('/home/n/q/nqdow...')<br />
#5 {main}
-->