Yeah, I checked all the folder and file permissions. Even tried transferring the "junk.txt" file back into the /sessions directory since debug seemed to think it should be there.

That didn't help.
Since I had a time crunch to update this calendar, I took the necessary three hours today to re-install the whole thing.
What I did was save some of the orig files from the templates/calendars/default folder so, at least, I didn't have to reset all of those.
after installation, I was able to copy over the installed files with my orig copies of:
preferences.txt
default.html
and it wanted styles.pl too
though that appears to be relic from older version?
So...bottom line....all works fine now.
That seems to point to something having got gummed up in the program, not browser problem, not web server problem...
I have a vague thought about whether this application hits a wall after a certain number of event or schedule entries? Didn't find any ref in docs to an upper limit on that. Doesn't *seem* like this should be a factor, but who knows?
I had two and half years worth of almost daily events. Maybe a factor...
I do still think this a wonderful application and I'm still (even after today) very glad to have taken the time to register it!