After waiting a bit longer, I discovered that there is a way to mark your tech support questions with a lower or higher level of urgency. About 20 minutes after I posted one of highest urgency, my problem was solved.
In case somebody is searching for insight into the bad_httpd_config problem in the future, here's what tech support said:
"It can mean any number of things. In general it just means that the domain did not get configured on the web server correctly for whatever reason. In this particular case it was because the logs directory for user 'ulnet' didn't get created automatically. Not sure why that happened but I've taken care of it."
I don't know for sure, but I may have made too many assumptions in setting up my system. I created the user "ulnet", I did Add Domain from the Web Panel, and then I manually created the directory into which the web files would go. I did not, however, create the logs directory. It makes me wonder whether the manual creation of the /home/ulnet/ultralingua.net/ directory may have screwed up some automated system or other.
Anyway, I am back to happy. I do hope they can bring response times back under 24 hours, however.