Singlepic stopped working upload problems

WordPress Multi Site: 3.1.3
NextGEN Gallery : 1.7.3
PHP Version : 5.1.6

I’m having multiple issues.

I’ve been using NG for a couple of years mostly w/o issue. Was previously using 1.6.2, then I tried updating to the new version but had too many errors. So I’ve gone back to 1.7.3 as recommended on Alex’ blog. Anyone know if v 1.7.3 also requires PHP 5.2?

Now when I upload I get some kind of generic error. Example:
ERROR: AHartline_CU_OLV04.jpg : 0

The image does appear to load. It’s in the manage gallery list and in the gallery itself.

However, singlepic doesn’t work right at all. Take a look at:
http://angelhartline.com/blog/?p=1517&preview=true

See where the pic should be? The pic is there. If you click that link the shutter view does pop up, so the db even knows the pic is there. But no matter what I try pics won’t show up in new posts. Here’s the kicker… they DO seem to be working in older posts. They weren’t at first but now seem to be there.

**I think something is wrong with the cache function. When I disable it old posts stop working, too. So maybe the error code has something to do with an issue with creating the cache for new uploads???

PLEASE PLEASE PLEASE can someone help me. I have too much on plate to spend so much time fighting with this. Thanks so much!