For BlackBerry there is a requirement for a BES 4.0+ server to be able to handle the JAR file since it is larger than 100k - which is a BES 2/3 limitation.
What BES server are you running? Did you follow the install instructions located in the "Install Notes" section of the "Sametime 7.5 Release Notes" located here:
http://www-10.lotus.com/ldd/notesua.nsf/0/cbfecf958ef471a7852571c50065d108
FYI - The 7230 is not a supported client primarily due to its slow processor and limited memory, however we realize people will probably use it anyway even if its unsupported. We're looking to address both native "Profile" integration and improve logon performance in our upcoming 7.5.1 release, so stay tuned.
Thanks,
--Mike