Go into Developer mode by going to Settings -> Security -> Developer Mode -> should be blue
Go to TERMINAL app which should now be on the bottom of your list of apps.

Type in the following with ENTER after each line
1. gconftool --recursive-unset /system/http_proxy
3. gconftool --recursive-unset /system/proxy
4. gconftool --recursive-unset /system/osso
5. exit

Twitter should now work on your N9.