1.Using Control Panel, Remove Desktop Manager from your PC
2. Using Control Panel, Remove ALL Blackberry device software (any Os's you've got loaded on your PC)
There shouldn't be any other BB software on your computer other than media manager if you initially installed it. What the hell -, Remove that one too.
3. Double check c

program files>common files>Research in Motion>shared>loader files. There should be no loader files listed here (you may not even have a shared file). Delete any loader files you find here (if any, they are memnants from OS that Control Panel did not fully remove).
4. REBOOT your PC after you remove the above from your PC
5. Install the Desktop Manager software of your choice. (4.5 if that's your choice but I've never had 523 issues with a good load of 4.7 or 5.0
5. Install .132 OS onto your PC
6. REBOOT your PC (worth the few extra minutes).
7. Double check c

program files>common files>Research in Motion>shared.
There should be only ONE LOADER FILE (.132) in that folder. If others are listed, PLEASE delete them!
8. delete the vendor.xml file found in C:\program files\common files\research In Motion\apploader and finally, attach your phone and ...
9. run the loader.exe program found in this same folder.
I hope this works for you.