[plt-scheme] mred in console mode on Debian

Hi,

I want to run mred under emacs. Running mred with the -z option seemed
to fix this until I tried the test case below

(define frame (instantiate frame% ("Example")))
(define msg (instantiate message% ("Hello World!" frame)))
(send frame show #t)

Which displayed a window of the right size, but no text within it. The
above does not work correctly running mred -z directly on the console,
however it does work when mred is run with no arguments.

What is the cause of this and how do I fix it?

Dragal