so today while i was updating my berry, my laptop died and my berry nuked... well, i reverted back to the t-mobile 4.2 os.... then i downloaded the above .52 and deleted the vendor.xml and the DM 4.6 still won't prompt me to upgrade
the desktop manager is still not recognizing the 4.5.0.52 software
I am not sure what exactly you mean by this?
You downloaded the .exe file... then installed to your PC.
So, in Add/Remove programs on your PC what is listed for RIM?
You should only have DesktopManager and the OS you want to load. You do not need to uninstall the other OSes, but I recommend it because sometimes a little confusion can occur.
Make sure the vendor.xml is deleted... and you should be good to go.
(As a side note : What OS is currently on your Berry? And did you wipe the device with JL as I said in the directions?)