Hi blestw4,
Well a False Positive is when a anti-virus scanner or part of it (heuristics) think that a good normal file is a malware file or that a good file behaves like a malware file that does more or less the same (behavioral find).
In the case of this legit good Microsoft made dll there must have been confusion with two files that has the same name hung to it and appeared as malware in the Sates and in Korea, if reports come in the avast coders get to work and take the false positive out rather quickly in most cases on the next update of the av-base if there is a real case of False Positive, users can check a file by uploading at virustotal.com if all scanners flag the file as malware it more than likely is malware, if only avast and another av solution that uses the same scanner flag it it can be a new detection or a False Positive, so whenever in doubt report these things here. Do you now understand what a FP is?
polonus
