ok yeah there is errors in you blockchain i think from that message.
in the %appdata% directory, open the Primecoin folder.
copy the primecoin.conf and wallet.dat out to another folder for safe keeping
now delete the entire primecoin folder in %appdata% directory.
restart the primecoin client and see if it downloads the blockchain correct this time...
If still same error try redownloading the primecoin client.
Failing that abandon windows and install Ubuntu on your PC and build the client from source!!
Hope this helps