Are you sure it has been locked, maybe it copies a very large file? Will it lock immediately when backup starts or in certain place. If so this is hint where to look for the problem. Don't have other suggesitons but check your source and destination paths, if you use remote machines there may be problem accessing the paths.
It worked when I changed the destination to my C: drive .... Why did it stop working on my CD Drive?? The CD drive seems to be functioning normally otherwise....I can even do a manual backup onto the CD but it still locks up in BM.... Any Ideas???
Perhaps you updated/changed your CD-writing software, after what BM did not copy files any more? If you are copying to a CD then the problem is your packet-writing software. See if there is an updated verison available or try re-installing your current one (first uninstall old one completely).