Well, it looks like the automatic upgrade problem was not WordPress, but my hosting company 1and1.com.
I searched around a bit more and came up with this excellent post by Michael Stults which fixed the issue. Thanks a bunch Michael.
I won’t rehash all that Michael has gone over, but it seems that 1and1.com was serving up PHP 4.0 instead of PHP 5.0, which WordPress was looking for.
A quick paste of these two lines before the closing tag of the .htaccess file makes it use PHP 5.0 and problem solved.
AddHandler x-mapp-php5 .php
AddType x-mapp-php5 .php
That’s all it took. Now all four of our WordPress sites are working right and automatically updating as they should.
Never even thought that you weren’t using php5. I did run into one today that I had a problem on a site and it was a plug-in that had to be deactuvated while I was upgrading. Then it worked fine. Reactivated it then and all was good. Had to do a little research for that one. It was the NextGen Image Gallery.
Glad you found out the problem.
Dennis,
Thank you for mentioning my post. More importantly I am glad that you found answers to your question. I know how much a pain in the rear this must be for a lot of people and especially for several who might not be aware of the fix.
Have a terrific upcoming week!
-Michael Stults
Michael,
You are welcome. You really saved me a WHOLE LOT OF TIME in fixing this problem and I am really thankful someone took the time to write a post about fixing your WordPress blog when 1and1.com screws it up by defaulting to PHP 4 instead of PHP 5.
Oddly, I had a problem last week. I clicked the button to update a post and boom, I got the infernal Internal Error 500 message and was locked out of the WordPress admin, plus the blog was offline.
Luckily, after I spent about five minutes panciking, I thought to check the .htaccess file and it was the culprit. Those two lines you told me to put in had gone away, poof! I added them back and everything was normal again.
Thanks again for your help.