Do you follow the steps in the link in post #4.
** At your own risk **
(it worked for me)
Uninstall 4.5 (go back to 4.2.2) [tip by Sith Apprentice]
install your last working OS (if it isn't already)
delete vendor.xml in program files\common files\research in motion\AppLoader
in DM click on Aplication Loader -> next
do a print screen to have a backup of everything that's checked
unselect all (yes)
next...
It installed all again.
I lost all the games.. but its working back again
Many thanks to jsconyers