Error after 10.10 Upgrade

[t3chn0b0y]

After updating to 10.10 I constantly get the following Error
Message.

warning, in file '/var/lib/dpkg/available' near line 147869 package'virtualbox': error in Version string '1.6.6-35336_Ubuntu_hardy': invalid character in revision number

[mörgæs]

The name 'hardy' is not comforting. Has the machine been upgraded since Hardy Heron?