Hello!
New guy here. I just installed 2.8.1 on my server. We have PHP 4 and 5 running at the same time. At first I had some problems so I added an .htaccess with php handlers in it (see example below).
AddHandler php-fastcgi5 .php .php5 .phtml
Still had problems but didn't get a 500 server error this time. So, I changed AddHandler to AddType (see example below) and everything started working on all 8 cylinders.
AddType application/x-httpd-php .html
So, if anyone has a similar problem, give this a try. I hope it helps. It might not fix all of your problems but at least it's something. Eh?
God bless!