The correct setting, perhaps the default now, in the php.ini file is to have the extension commented out:
So make sure the extension looks like this in .\xampp\apache\bin\php.ini
Save the file and restart Apache (that's stop and then start Apache) - did you do this step also?
Check that it is disabled in the phpinfo() from the XAMPP welcome page at http://localhost
I have edited my first reply to reflect this.
Other related extensions in the php.ini file - these are from my php.ini file and how they are configured, if that helps any:
Can you paste here any specific error messages please?
In this Google Search
is there anything of interest for your issue?
And this Google Search
From the above search results:
http://www.theregister.co.uk/2008/08/15 ... g_xml_php/
..and I am sure perhaps there is some info in the official php manual.
Also you could try making inquiries at the web sites of the scripts you are trying to install.
Your scripts may not be compatible with php5.
Others have had success by uninstalling then reinstalling the scripts again.