<div> Hi guys, I am a freshman student in Kenya. After I stumbled on MIT's ocw website, I got interested in Scheme and after a few while on this LtU site, I felt like starting with DrScheme is the best way since its tailoured to the biginners. I am very new in Programming and we just don't have great teachers who have command of the subject here in Kenya. Well after installing and running DrScheme, I encountered a problem which I will be very greatful to anyone of you who can help. I difined this procedure: (define (area-of-disk r) (* 3.14 (* r r))) which worked when I ran it like this (area-of-disk 5) then I defined this: (define (area-of-ring outer inner) (- (area-of-disk outer) (area-of-disk inner))) However upon running this procedure I got this message; area-of-disk: name is not defined, not an argument, and not a primitive name. and this on the tracing window: No tracing results are available, yet. (Make sure that your language supports tracing and that tracing is enabled.) Can anyone help?</div> -- Live, Learn, Love! Patrick Amkayah.