Exactly the same error, I was playing fine on test logged out to transfer a character and when I tried to log back in got a manifest check download and then the error, got past the first error only to get an error about a bad install. I then did a verify all files and it went back to the piggs/soundVMusic7.pigg error.
Here is the clipboard copy of the next error if you go past the music7 error:
Failed to load texture library. It is likely that City of Heroes is not properly installed. Re-installing or running CohUpdater may fix this.