Install Jamroom 5 - PHP System Error
Installation and Configuration
I'm not 100% sure, but moving the php.ini file to the JR5 directory may not work.
Can you edit the php.ini file in your /etc/ directory, as stated in that post, and restart your server?
If you can't edit that file directly, you may want to contact your hosting provider for assistance.
Short of that, you'll want to wait on Brian, he know more about the server setup than I do.