Do you mean if you open bridge from within photoshop cs6, that bridge cs4 opens instead or something else?
What operating system are you using?
If while in bridge cs6 the photos want to open in photoshop cs4, you should check under Edit>Preferences>File Type Associations in bridge and change the relevent ones to photoshop cs6.
Thread moved from PS Beginners forum to Bridge General Discussion forum
If you uninstalled a prior version after installing CS6 it may have fouled up the registry. Post back if above does not work.