[plt-scheme] problem using drscheme tools

Hi,

I'm having problems using DrScheme Tools.  I'm trying to add a new
language by creating an implementation of drscheme:language:language<%>.
The docs claim that the FRONT-END method should return a syntax object
or sexp, but when I return any simple sexp such as `(display "hi
dave"), I get the following error:

compile: bad syntax; function application is not allowed, because no
#%app syntax transformer is bound in: (display "hi dave")

Any clues?  Thanks,

Dave