I don’t know the ‘why’ of the problem yet but I wanted to post this for anyone having similar problems. Initially I’d installed the ‘tetex’ distribution using fink, version 2.0.2-34. At first nothing worked – if I ran pdflatex against some of the samples in the beamer distribution I’d get a completely black slide – no text, no graphics, nothing.
Later I found the beamer setting 'beamertemplatesolidbackgroundcolor' and set it like this:
\beamertemplatesolidbackgroundcolor{white!100}
This gave me a white background and I could see text, but the navigation items in the menubar didn't work properly for some themes -- there'd be a block of black where the highlighted navigation item should have been. Finally I found a theme that minimized the faults I was seeing which allowed me to focus on the important part, the content -- content is king, remember?
But as my work on the presentation wound down yesterday it started to bug me again, particularly since I was only able to view the generated PDF in OS X Preview. Opening it in Acrobat (PC or Mac) gave me a 'unrecognized token "gray" was encountered' and another error message that escapes me at the moment. Annoying!
So just for laughs I decided to try another distribution. I didn't think it would actually solve anything since all main TeX-related stuff is so old and therefore wouldn't change much. I grabbed the TeX-fat i-Installer disk image from a helper site (just shy of one-half the way down) and installed it. Once I reset my TEXINPUTS variables to leave out the fink-tex directories and just point to the items in my home directory (where beamer and a couple of supporting packages were unpacked) everything worked!
Did the fink install leave something out? Did I actually just have something incorrectly set in my TEXINPUTS and coincidentally changed them with the new software? Is it a version difference where an intermediate patch took care of my problem? No idea, but i'm not touching anything until after the next presentation...