Sounds like you have the wrong version of googlemaps installed.
Delete it entirely before re-installing, then when you install google maps, make sure your browser identification is set to identify itself as "Blackberry browser" and not something else like firefox etc...
You can find the identification by opening the browser, bbmenu -> options -> Browser Configuration -> Browser Identification.
Bad news !! Goggle maps are not working well wit the new .607 OS . After upgrading to the new 4.0 version the application become unresponsive when you try to search . I tried to delete and reinstall and i have the same problem and finally i reinstalled the 3.2.1 version and guess what , problems with searching are still present . Seems we have to find a different maps app until we get a new OS leak from RIM .
Some nice features, and it does seem to get a gps lock way faster (which is pretty big for a map app, right?) But it also seems to be slowing my berry down a bit. Too big methinks
Posted from my CrackBerry at wapforums.crackberry.com