What error do you get if you try to delete it without checking first?

 Code:
   $RC=delprinterconnection("\\server\HP LaserJet P4014 PCL6")
   ? "result: "+@Error+" - "+@SError

   $RC=delprinterconnection("\\server\HP LaserJet P4014/P4015 PCL6")
   ? "result 2: "+@Error+" - "+@SError