Problem Resolved:
However, the resolution was not smooth. First, I decided to try setting up a second installation of Zenphoto so I could do a clean install of the 1.0.8 version. First step: create a new database on my ISP server. Bam. Just creating the database killed the installed photo album. Oh, well, I was going to do a clean install for a test, now the test would be "live".
I cleaned everything out, dropped the database(s), set up a new database, copied all the appropriate files. Tried to run the setup.php script. No dice. Had the login problem(s) described above.
So, I went into my browser cookies and found the ones the album placed there. Deleted them and ran setup.php again. This time I was able to log in.
All is well now.
There may still be a problem with trying to change the Admin user and/or password. I haven't tried that on the 1.0.8 version. I have also not tried adding a new database on my server--that was too sever a problem, don't want to experience that again.