The krfb application is used when you want to allow someone to connect to and/or take control of your computer using a VNC client. One thing that can really slow things down is when krfb insists on sending the background image, also called wallpaper. This slows down the connection with gobs of needless extra data from drawing and redrawing the wallpaper every time you open, close, or move a window. It can slow things down to a crawl while the person helping you waits and waits for your screen to refresh in their VNC client so they can see what your system is doing.
This might be a simple matter to fix, if your version of krfb includes a menu option on the Session tab to Always disable background image. But if it doesn’t, as is the case with krfb in openSUSE 11.1, what do you do?
Well, you can manually edit a file called krfbrc , most likely in your ~/.kde/share/config directory. That is, the absolute path will probably be /home/yourusernamehere/.kde/share/config/krfbrc. Make sure krfb is closed, then open this krfbrc file with your favourite text editor and add the following line:
disableBackground=true
Save and you’re through! When you launch krfb, it should now start and make a connection without wasting valuable bandwidth on sending the wallpaper over and over again..
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g33kgrrl's garage 
Where in the krfbrc file to I place that line? Would it be under main window, invitation_0, or invitations? Thanks in advance!