Make sure you have installed the correct plug-ins included in the Mbox Factory Bundle, and that you are not seeing authorization screens for demo versions. Some details about exactly which plug-ins are included in the bundle in this thread:
http://duc.digidesign.com/showflat.php?&Number=881391
To remove demo versions of plug-ins and optional software:
http://answerbase.digidesign.com/detail.cfm?DID=28112
Also, since you have updated to Pro Tools LE 6.9.2 and Tiger according to your other post, make sure you download and install the current iLok drivers:
http://www.paceap.com/dldrvr.html