Error: Unable to make thumbnail (0) with netpbm

The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful):
Gallery version: 1.51
Apache version:19990320
PHP version (don't just say PHP 4, please): 4.4
Graphics Toolkit: netpbm
Operating system: linux
Web browser/version (if applicable): ie6

i get the following when i try to add a photo:

Doing the naming
Image Preprocessing
Resizing/compressing original image
util.php::481 -> Resizing Image: /home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg
util.php::329 -> Getting Dimension of file: /home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg

No resizing required
Adding Photo to the photo list
util.php::989 -> File /home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg type 2.
util.php::329 -> Getting Dimension of file: /home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg

Generating thumbnail.
util.php::481 -> Resizing Image: /home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg
util.php::329 -> Getting Dimension of file: /home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg
util.php::277 -> Executing: '/home/dwaynek/public_html/netpbm/jpegtopnm' '/home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.jpg' | '/home/dwaynek/public_html/netpbm/pnmscale' -xysize 150 150 | '/home/dwaynek/public_html/netpbm/pnmtojpeg' --quality=90 > '/home/dwaynek/public_html/photos/album04/Resize_of_PICT0079_005.thumb.jpg'

Results:
none

Debug messages:
pnmscale: Error reading magic number from Netpbm image stream. Most often, this means your input file is empty.
pnmtojpeg: Error reading magic number from Netpbm image stream. Most often, this means your input file is empty.

Status: 1 (expected 0)
Error: Unable to make thumbnail (0)
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