[racket] ffi/com

Hello,

during playing arround with the ffi/com package I try to do something like that:
(require ffi/com)
(define cci "com-create-instance")
(define ProgID " MzCOM.MzObj")
(define mz (string-append cci ProgID))
(eval mz)
but I get only the string. Or something like this:

(define (cci VAR PROGID)
	(define VAR com-create-instance PROGID)
)
I get :define: bad syntax (multiple expressions after identifier) in: (define VAR com-create-instance PROGID)

So I thing I understand something wrong here. Or is this what I am trying to do possible?

Thanks. Yours, Murat