Thumbnails Not Generating

Slideshow Gallery works well except that I would like to add thumbnails to my slideshow. While the images display fine the thumbnails will not generate when an image is uploaded/linked to.

In Chrome the typical ‘image was supposed to be here’ icon appears. In Firefox a 1px x 1px empty box appears for each thumbnail that was supposed to be there.

When I select a thumbnail and click view image I get the following error:

A TimThumb error has occured

The following error(s) occured:
Could not find the internal image you specified.

Query String : src=wp-content/uploads/slideshow-gallery/Painted-Car.jpg&w=100&h=75&q=100&a=t
TimThumb version : 2.8.10

Any guesses as to what is going on?

http://ww.wp.xz.cn/extend/plugins/slideshow-gallery/