There is a problem with the Deploy, I have run into the same thing.
in a text editor take out the "%windir$\ehome\RegisterMCEApp.exe /u commercialskipaddin.exe" and save the file..
If you have already unregistered "CommercialSkipAddin.xml" reregister it by doing the following
Open an elevated command prompt and get to the directory that has "Commercialskipaddin.xml" in it by changing the directory (example: C:\Windows\System32>cd \win7dtbaddin)
Then execute the following command:
"%windir%\ehome\registermceapp.exe /allusers commercialskipaddin.xml" (without the quotes)
This will reregister the old addin that you need to have the DVRMSTbSettings work right. You have to go into the extras library to disable "Commercial SkipAddin" (not DTBAddin) and you'll be fine.
This crap took me over 4 hours to figure out, I also re-installed my OS two times.
If you have a lot of shows cutting off, there is a problem with the WTV Converter in some of these beta verisons. The best I have found is 7077, however 7057's was pretty good and RC1 will not do a show longer than an hour. So, what version are you using?