Need help with CI and HTML2PDF service

[eluser]aryan_[/eluser]
I'm using http://html2pdf.seven49.net/ to convert html file to pdf. I've allowed +=a-zA-Z 0-9~%.:_\-? characters in URI and URI Protocol is REQUEST_URI.

I'm getting this db error:

A Database Error Occurred
Error Number: 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for
the right syntax to use near '?LCSMLCU=SCCTELG LIMIT 1' at line 1
SELECT * FROM artworks WHERE artworks.id=184?LCSMLCU=SCCTELG LIMIT 1
Generated

How query is ok:-
$sql = "SELECT * FROM artworks WHERE artworks.id=$art_id LIMIT 1";
$query = $this->db->query($sql);
$data['art'] = $query->row();


A sample page uri is- http://www.rareartist.org/admin/pdf/184

Can you please help me?

Thanks!