Sometimes Mozzila firefox browser gets errors but don't worry. Try below hacks to speed your firefox.
1. Type “about :config” in the address field.
2. Set the value of network.http.pipelining to “true”.
3. Set the value of network.http.pipelining.maxrequests to “100″.
4. Set the value of network
http.proxy.pipelining to “true”
5. Set the value of nglayout.initialpaint.delay to “0″ (if availible in newer versions)
If your have any problem leave a comment...