Whenever you import a document (like DOC) to Google Docs and save it there, a *.gdoc link file is automatically created on your computer. This acts as link to the document and does not contain the actual document data. In that sense, no DOC to GDOC conversion is actually possible.
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.