I had the same problem
I thought first I had a virus
I deleted my site using ftp
then uploaded
– new wordpress installation
– my backup wp-content folder with plugin folder from another site that was working and had the same plugins
I also tried to rename the plugin folder
But no change.
Then I read this and saw that others also used arvixe
it hit me that it had to be them
so i checked the htaccess file for the installation
and compared to one that was working
the difference was one added line at the top of the file on the domain that didnt work
AddHandler application/x-httpd-php52 .php .php5 .php4 .php3
(# change php version to PHP 5.2)
I removed it, and voila!
