AVG has a great heurstical scanner. For virus software, heuristic algorithms are "smart software" which detects new and unknown viruses.
It could either be an uknown virus, or a spyware. "Dropper" could very well stand for spyware, which AVG often detects as unknown viral bodies. So it may be relatively harmless.
And not all... Any, I mean... virus scanners are perfect. This could be a mistake too. Kavsperksy also has a great heuristical scanner and will detect many spyware / adware related programs as potential threats. But about 99% of the time, you'll find it is best to remove these things anyway.