Shame on me for reporting this and then getting lost in RL for three months without following up! I just installed your update with the improved error reporting (1.28.2.38) and it still has trouble navigating the windlight folders:
To address your concerns that my filesystem may be broken, I made these changes:
Completely wiped out the old installation so the installer went to a clean directory
chmod -R 777 /pub/games/SecondLife
changed to a different user who has never run SL before (so no ~/.secondlife folder)
installed as root to a completely different partition (/usr/local instead of /pub/games)
copied all of the install path's app_settings/windlight and subdirectories into the new user's ~/.secondlife/user_settings folder in case it worked better to find the files locally
None of that helped. I agree that it must be something uniquely wrong with my system else you'd be hearing from thousands of other users... I'm just at a loss why it doesn't like those paths. I should also mention that I have been running Cool VL Viewer for at least five years, and only in June did I start seeing these errors. Every update I have always renamed the working folder to a new folder and installed fresh, so I wasn't conflicting with old files. Something must have changed.
Oh well, at least I can fall back to the previous version until I figure out what I broke.