I am running InkSaver on one of my printers (Canon S600) and have not had this problem (Windows ME). It could be an XP problem. I would try uninstalling the printer and reinstalling, making sure you have the latest drivers from the Canon site (click here).
It might be worth checking the InkSaver site for support as well. Can't remember the address (I'm not on the PC where it's installed) but I think there's a link from within the program.
Hope this helps.