Got Ubuntu installed but having Firefox problems
 

When I open different pages I get the following message.

XML Parsing Error: syntax error
Location: chrome://mozapps/content/plugins/pluginInstallerWizard.xul
Line Number 1, Column 1:Components.interfaces.nsIUpdateManager);
^

If I try to download anything, like trying to install the newest Firefox I click on the link to get the file and I get:

XML Parsing Error: syntax error
Location: chrome://mozapps/content/plugins/pluginInstallerWizard.xul
Line Number 1, Column 1:Components.interfaces.nsIUpdateManager);
^

What can I do to resolve this?

Try..

sudo apt-get remove mozilla-firefox
sudo apt-get install mozilla-firefox

This will remove and install it (I'm not exactly sure if the package name is 'mozilla-firefox') if not do

apt-cache search firefox and see the packages listed. Or..as a total alternative try using a different browser. sudo apt-get install opera and then download firefox from there.