I didn't even notice when you first pasted this in IRC that it's a warning, not an error. So, yeah, I don't suspect this is bug-worthy in dpkg either, it's just expected behaviour for it to yell about bad version numbers.
Cleaning out your crufty dpkg available file with "dpkg --forget-old-unavail" should make it stop whining.
I didn't even notice when you first pasted this in IRC that it's a warning, not an error. So, yeah, I don't suspect this is bug-worthy in dpkg either, it's just expected behaviour for it to yell about bad version numbers.
Cleaning out your crufty dpkg available file with "dpkg --forget- old-unavail" should make it stop whining.