Sorry, I copied the wrong message…
The problem is not that they SUPPORT PHP4, it’s that you WANT PHP5. Add this to your .htaccess if you’re at 1&1.
AddType x-mapp-php5 .php
That will force *.php files to be processed by PHP5. That should resolve the problem for you.
How do I do that? I am not great with coding so I’m not really sure what to do.