RSS blank line error

I have the super-awesome blank line error with my rss feeds, seen here:

https://www.jimhodgson.com/feed/

I have disabled all plugins, and the problem remains. I have switched to the default theme and the problem remains. I have switched to the default theme AND disabled all plugins AND searched wp-config and wp-rss and functions.php, all to no avail.

I went ahead and upgraded to 2.8.6 and the error persists.

I have installed the fix rss feeds plugin, which reports a blank line in _every file in my web directory_. I looked in all these files by hand and it is lying. There are no blank lines outside of <? ?>.

I also tried to install the php linefeed fix here: https://wejn.org/stuff/wejnswpwhitespacefix.php.html but it requires php5 and I am on php 4.4.9

I have done everything I know to do and I can’t get my installation of WordPress to act right.

So, any ideas appreciated! Please help!