Can not back up, need help

I re-installed the DTM but now it won't even sync. It will show the files and photos but will not sync or back up. It gives me a message that the device is not properly connected. I tried to back up after disabling the WIFI, still no good. I have a lot of files and don't want to loose them after I try to update to the new OS so I really want to do a back up. I am still worried about problems with WIFI after the OS update but with out doing a back up I don't want to even try the OS update. Any suggesstions?

OK, I was able to do a custome (file and settings) backup after turning off the PB, hooking it up to the DT with DTM open then turning the PB back on. I was not able to do a full backup with the apps even though I had already deleted most of the unnecessary apps and games. I am still not able to sync. After all this I think I will wait until they fix the latest OS update, I really don't want any more headaches and if I loose the WIFI I will be in deap trouble.