Image uploading has me stymied

Not an uncommon problem for fancy CMS systems, and Drupal is no exception: I can't figure out what's wrong with my file upload settings. Specifically, I can't upload images, right now, as the site's currently set up. Now I get to find out just how supportive the "open source" community can be. Honestly I almost wish I could just spend $50 and be guaranteed a quick reply.
In the mean time, this means I have to make do with simple text pages, no links to documents, no links to PDFs, no thumbnails, nothing at all fancy. Probably a worthy marketing exercise in any case -- can I make my case based only on my words?
I think my first commercial release of a Drupal-based site is coming up soon, for the Animal Defense League of Arizona. They're old friends and I appreciate their cause, but they're in dire need of a community portal solution and I think the tools I now have available will do the trick nicely...assuming I can hammer out this ridiculous file upload issue.