Arios,
Thank you very much for your reply! Nice to know I'm not the only one with the problem.
As you suggested, I tried the latest version of epubstar, but got the same results as with the previous version.
However, I now have gotten excellent results from using two very different methods.
First, I used MS Word to create an RTF file of my 4-page test epic, which includes many bullets, screenshots and links. Next, I opened it with Calibre and converted it directly into the EPUB format. It took me a lot of trial-and-error and back-and-forth in Word and Calibre until I got things right, but I finally got it to look good.
Then, after reading your suggestion, above, I downloaded the Writer2Xhtml plugins you recommended and installed them into Open Office (which I already had). I opened my RTF file in OO just as it was at that point, exported it to EPUB, and opened it in Calibre. It was even better than the RTF-to-EPUB! This is definitely the way to go!
I appreciate your recommendation. It saved me a lot of dangerous downloading of shady software and wasted effort.
Frank