Why is Automator not working with Spotlight Search?
What happens if you try in terminal.app (change /Search/Directory/ to yours):

mdfind -onlyin /Search/Directory/ kMDItemFSName == "\"NUCLEUS SOUNDLAB Pantheon III.rfl\""


Or in applescript editor.

    set searchPath to "/Search/Directory/"

    set this_item to "/Users/USERNAME/Desktop/NUCLEUS SOUNDLAB Pantheon III.rfl"

    set theFileName to "\\\"" &amp; (do shell script "basename " &amp; quoted form of (POSIX path of (this_item))) &amp; "\\\"" as string

--set theFileName to quoted form of (do shell script "basename " &amp; quoted form of (POSIX path of (this_item))) as string

  set theOrigFilePath to paragraphs of (do shell script "mdfind -onlyin " &amp; searchPath &amp; " kMDItemFSName == \"" &amp; theFileName &amp; "\"")