[magick-users] Convert PDF->JPG works in command line, not in PHP

[Brian Dunning]

Here's a weird thing. I have a new Redhat machine, with PHP 5.2.6 and  
IM 6.4.8. The following works beautifully on the command line:

convert original.pdf new.jpg

But from PHP, it only works beautifully if I specify complete  
pathnames for convert, the original file, and the new file (that's OK,  
no problem), but it only works converting JPG and GIF images. As soon  
as I try to convert a PDF image, it fails:

<?php
$command_line = "/usr/local/imagemagick/bin/convert  /var/www/html/ 
original.pdf /var/www/new.jpg";
system($command_line, $return_var);
?>

$return_var = 1. Any suggestions?