I am not sure what could be doing it if you are totally stock.
A couple things to try/look at.
I don't know at what point the app crashes your phone, but if you are not "signed in" to GMapps, do so on your phone if it doesn't tank it right away. I have had freeze ups while accessing GMaps when not signed in.
I am used to using nandroid to back everything up, so, at your discretion uninstall - reboot- reinstall and sign in to GMaps.
Otherwise maybe GMapps is using too many phone resources and you don't have enough free memory and the phone reboots - or further, there is something wrong with the phone itself when put under load (CPU access +GPS, etc).
Nick