debugging timthumb (shoot me and put me out of my misery)

[PogoFan]

Still can't get thumb working. Those of you who have timthumb working properly:

When you upload an image using the flash or browser method but don't insert the image into the post and "save all changes," do you then see that image listed in the /cache folder? If not, does it show up in /cache after you save the post or when you publish it?

I did some more testing this morning and realized that when I use the (required) method of uploading the image I want to resize to use as a thumb, that image does not show up in /cache even after I save and publish the post. The image does show up in the Media gallery, and when I hover over it in media gallery, it shows a url with the structure:
.... /wp-admin/media.php?action=edit&attachment_id=(number). I also checked and noted that the uploaded image is showing up in wp-content/uploads. Yet all I get where the thumb should appear on the homepage is hyperlinked text.

My server error logs suggest that the script is being called and I get no error message about GD library. What I get are error messages like:

[Wed Jun 17 17:15:45 2009] [error] PHP Notice: Use of undefined constant IMG_FILTER_NEGATE - assumed 'IMG_FILTER_NEGATE' in .[mydomain]/wp-content/themes/streamline_30/tools/timthumb.php on line 30, referer: [mydomain]
[Wed Jun 17 17:15:45 2009] [error] PHP Notice: Use of undefined constant IMG_FILTER_GRAYSCALE - assumed 'IMG_FILTER_GRAYSCALE' in .[mydomain]/wp-content/themes/streamline_30/tools/timthumb.php on line 31, referer: [mydomain]

etc. for all of the other constants the script uses. So it seemed to be calling the script, but I have no idea why it's reporting undefined constants. I haven't edited the timthumb.php coding at all.

Does my description of findings suggest to anyone where the problem might be (other than between my ears)?

I'm really frustrated by now. I got this theme because of the feature to create auto-sized thumbnails. I've now spent more than 3 days and can't get my site to look the way I want it to look.

If no one here can help me get it working, is there an alternative that you could recommend? I did some searching last night and found a few possibilities, but they are so poorly documented that I cannot figure out how to use them and I am obviously not a coder. Would StudioPress consider providing customers with an alternative to timthumb with a tutorial?

Thanks for any help you can offer.