Welcome to the forum.
Until just the other day, I had never heard of PrE Quick Editor, but it seems to be a limited program, sold from the App Store, for a Mac.
There might be some tips that can be extrapolated from this recent thread: http://forums.adobe.com/thread/1272658?tstart=30
Not specific to MTS files, the OP was trying to locate their media files in other folders, than those indicated by PrE Quick Editor. The extrapolation would indicate that the program definitely wants the media files in those specific folders.
If PrE Quick Editor will handle MTS files, I would Copy the entire folder structure, with the media files (all folders), to the My Videos folder, and then Import the media files from there. I do not know if PrE Quick Editor has the same naming conventions, as PrE 11 does, but in PrE 11, one would use Add Media.
You may want to check out the following
"Premiere Elements Quick Editor/Getting Started"
Please let us know if that helped.