BlackBerry Pearl 8130

my buddy has the pearl and i tried hooking it up to his computer using that desktop manager for black berrys, software.. everything worked fine until i went to the application loader to install some themes i had him download and it said that the phones software was not right and to contact verizon or RIM ... does anyone have any ideas on what would cause this problem or how to fix it .. i suggested going to the verizon store and getting a software upgrade (he has had the phone for roughly a year and there must have been an upgrade since then i would assume)

thanks