Both VMC and PVS files are just configuration files from virtual machines (Microsoft Virtual PC and Parallels), so there is no way how to convert them between each other, including vmc to pvc conversion. You need to convert whole virtual machine, that means all the related files at once.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.