LOGO-L> if touching?

[Pete Gerum <gerump001@hawaii.rr.com>]

I'm trying to get  some action to take place when two turtles touch,
but I keep getting this message   ( fd didn't report anything
to touching?)  in the folowing procedure.
Could someone please help me clean it up?

To Go
if colorunder = 15 [ announce [You Win!] stopall ]
if touching? [setup]
fd speed
end
 

Setup would return the two touching turtles to a starting point.
Speed is a slider

So why do I get the above message?

Also, if I have multiple turtles on the screen - how would I designate the touching of  two specific turtles?
Thanks for the help.