Well, my host (aplus.net) did a check that PHP was “working fine” on my account and didn’t want to help me beyond that. As they said:
“We do not debug second or third-party code, therefore the errors generated would be originating from the php script used.”
I did a little digging myself:
Here’s hoping that WordPress 1.3 will be more compatible with aplus.net’s installation.
Next thing to try: unpacking the wp-rss2.php file from the nightly build of WP1.3 and see if it can be plugged-in to my my 1.2 installation.