JPEG 2000 support was added in 4.3.2, so if they have earlier than that, this MAY be the problem. I'm just making a stab in the dark, though.
An easy way to get information on a PHP install is to make a PHP file that consists of:
<br /><?<br />phpinfo();<br />?><br />
Call the file from your browser and it'll give you all kinds of goodies about the server's PHP install.