When you start FireFox sometimes you get this erorr. I am not sure what course this error.
XML Parsing Error: error in processing external entity reference
Location: chrome://browser/content/browser.xul
Line Number 18, Column 1:
%browserDTD;
You can simply fix this error by runing the FireFox setup again on top of current installation. You do not need to uninstall your current FireFox.
If you have important bookmarks better to take backup of your profile by coying the folder
(In Vista : App Data > Roaming > Mozilla > FireFox > Profile ) to Desktop or some other secure location.
