Hello,
SpyBot Search and Destroy has a feature called
Imunization.
This feature works like this: it creates in the registry some bogus entries (which, by name, belong to known malware infections). The idea behind this "fake" infections made by SpyBot is exactly like a vaccine for humans: offer the computer a small dose of the virus, so it won't get infected

In other words, if a real infection should arise, the real malware will find the registry entries in the registry and it will "believe" that the system is already infected, so it won't proceed with infecting the system (thus it will remain clean).
So, practically, YahooAntispy (which I'd remove, if I were you, since I never heard that it has a good detection rate) detects a real, but totally harmless, thing.
Because it's not a real infection, BitDefender will not add a signature for this, so it will remain undetected.
It's your choice what you do next:
- either keep using SpyBot's Imunization, and remove YahooAntispy from your system
- either quit using SpyBot Imunization
Personally, I'd go with the first choice: remove Y!ASpy.
Cris.