Cannot Post Images (cannot create thumbnail)

Gallery URL (optional but very useful): www.nachas.us/gallery
Gallery version: 1.4.4-pl2
Apache version: Apache/1.3.29
PHP version (don't just say PHP 4, please): PHP Version 4.3.8
Graphics Toolkit: NetPBM
Operating system: Linux
Web browser/version (if applicable):
_________________________________________________________
I'm getting: Error: Unable to make thumbnail (0) when trying to upload images. I've put the app in debug mode but not getting much information. Also, I have executed the php code <?php
echo ini_get("disable_functions");
?>
and did not get exec()

The full text is:
Fetching Urls...
/homepages/27/d93864291/htdocs/nachas/pics/0002.jpg
Processing status...

- Adding 0002.jpg
Resizing/compressing original image
No resizing required
File /homepages/27/d93864291/htdocs/nachas/gallery/albums/album01/0002_G.jpg type 2.

Executing:

'/homepages/27/d93864291/htdocs/nachas/netpbm/jpegtopnm' '/homepages/27/d93864291/htdocs/nachas/gallery/albums/album01/0002_G.jpg' | '/homepages/27/d93864291/htdocs/nachas/netpbm/pnmscale' -xysize 150 150 | '/homepages/27/d93864291/htdocs/nachas/netpbm/pnmtojpeg' --quality=90 > '/homepages/27/d93864291/htdocs/nachas/gallery/albums/album01/0002_G.thumb.jpg'

Results:
none

Debug messages::

Status: 255 (expected 0)
Error: Unable to make thumbnail (0)
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thanks in advance.

Amansker nailed it...I had the wrong version of Netpbm

http://gallery.menalto.com/index.php?name=PNphpBB2&file=viewtopic&t=20480