I think I might have found the problem. Although I'm not sure how to fix it.
The XS++ log in post #15 shows the following line of code when I load my custom pack...

Code:
10:02:58| Custpack: AMERICA_2 (CDA102460/101) (K510)
I believe the custom pack is wrong because it states K510. However I have a W580.
When I looked up the K510 i found that it's native resolution is 128x160 pixels, but my W580's native resolution is 240x320 pixels. This might explain why my screen is distorted and stretched.

But I'm confused as to how to fix this. The custompack I used is straight from this site and is labeled w580. Is the custompack on this site wrong?