I got a real virus hit that Norton warned me about but I would have ignore the rock.exe file as a matter of policy from anyone let alone a couple who would not (in my estimation) want to play "a excite game" (sic). It really is a matter of logic - does the person telling you this know what they are telling you? Are you confident of the PC literacy of the person who told them. OK a warning is a warning - so ask someone who does know about these things.
The problem with the sflnbak.exe hoax is that a genuine virus now uses a file with that name.
Sucker punch?
Solution? - Norton! et al.