I traced it to the .htaccess file. When I was bringing up my site, the ads wouldn't show and the .php wouldn't execute. And sometimes my Browser would try to download the webpage instead of just view it. So I went back and forth on tech support with my ISP LunarPages.
Seems they run something called suPHP and the contents of .htacess must be:
AddType x-httpd-php .php .htm .htm
(notice it doesn't have the 'application/' in it.)
I guess suPHP doesn't like the 'application/' .
I am new at this, but it might work for you if you are having a rough time..
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