[racket] sllgen:make-rep-loop in Racket 6.1

I've just updated my Racket installation to 6.1 (Windows 64bit), and
something seems to be strange with sllgen:make-rep-loop: Although the
auto-completion finds it (and other sllgen stuff), it seems to be
unbound. Tiny repro:

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#lang eopl
(display sllgen:make-rep-loop)
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The output (in German, but I think you get the point):

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Willkommen bei DrRacket, Version 6.1 [3m].
Sprache: eopl [angepasst]; memory limit: 128 MB.
sllgen:make-rep-loop: unbound identifier in module in: sllgen:make-rep-loop
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If I run the same program in Racket 5.3 (Linux x64), I get:

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Welcome to DrRacket, version 5.3 [3m].
Language: eopl; memory limit: 128 MB.
#<procedure:sllgen:make-rep-loop>
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Is this a bug in 6.1 or am I doing something wrong? I've discovered
that while trying out my old EOPL exercise, which don't work
anymore... :-/

Cheers,
   S.