GET and POST request not working for a ip-address (Internal server error)

Question

I am working on an application which I have to migrate to another server ie Amazon.Now I created an EC2 instance,configured it and installed the application.All is fine but my ajax requests are giving me an internal server error 501 message.
I have the same application running on a different domain(I am migrating it to Amazon ) and it works fine.On amazon I have an ip-address at which the application runs and it does not have a domain name.(ie XXXX/home.php ). I cross checked the paths by trying both absolute and relative urls,but I still get the same error,even though the file is present.
Also,I tried changing the permissions from 644 to 755 ,but no result.
I would like some inputs over if this is happening because I don't have a domain name yet for the IP (It works fine on my old server which is a godaddy one and has a domain name pointed to it)?

Answer 1

PHP 5 should come with dom enabled by default. Which you can check by inspecting the php info output.

dom

DOM/XML enabled
DOM/XML API Version 20031129
libxml Version  2.7.8
HTML Support    enabled
XPath Support   enabled
XPointer Support    enabled
Schema Support  enabled
RelaxNG Support enabled

If you are using PHP 5 and for some reason dom is not available. Check for a package in your repositories called php5-xml