The default setup of SCIM on Gutsy and Hardy produces some irritating errors including the inability to rename files in Nautilus (Gutsy), inability to type jump to files in Nautilus by typing the first few letters (Hardy), and Firefox 3's URL matching in the location bar lagging by a character (Hardy).
All of these problems can be fixed by installing scim-bridge and using that instead of xim.
To install scim-bridge on Gutsy using the following command
sudo apt-get install scim-bridge
To install scim-bridge on Hardy using the following command
sudo apt-get install scim-bridge-agent scim-bridge-client-gtk scim-bridge-client-qt scim-bridge-client-qt4
Now open the scim config file
sudo gedit /etc/X11/xinit/xinput.d/scim
and chage the following lines
Restarting SCIM is not sufficient so restart X either by restarting the computer (System->Quit->Restart) or hitting [CTL][ALT][BACKSPACE].
Source of this fix from here