I would try rebooting your iPod just before you start the game. Also I would use sb settings to make sure you have plenty of free memory... more than 25MB.
oh I didn't know it uses a lot of memory. is there a way to stop backgrounder from running programs without me having to find each app that i'm using it on?
Go into the backgrounder app and go to app-specific settings and switch to the beta version, then when you hold down the home button a screen will come up and you can close specific apps.