[plt-scheme] Twitter in PLT demo

Jay McCarthy wrote:
> In honor of Twitter ditching Ruby, here's a quick demo of Twitter with
> PLT (pronounced Pwitter)
>
> wget http://faculty.cs.byu.edu/~jay/tmp/200904061550-pltwitter.tar.gz
> tar xzvf 200904061550-pltwitter.tar.gz
> cd pltwitter
> mzscheme -t run.ss
>
>   
It was main.ss but this is what I got anyway.

$ mzscheme -t main.ss
test.ss:3:9: schemeunit: standard-module-name-resolver: collection not 
found: "schemeunit" in any of: 
(#<path:/home/jon/.plt-scheme/4.1.4.3/collects> 
#<path:/home/jon/bin/plt/collects>) in: schemeunit
setup-plt: error: during making for 
<planet>/jaymccarthy/ring-buffer.plt/1/0 (Ring Buffer)
setup-plt:   test.ss:3:9: schemeunit: standard-module-name-resolver: 
collection not found: "schemeunit" in any of: 
(#<path:/home/jon/.plt-scheme/4.1.4.3/collects> 
#<path:/home/jon/bin/plt/collects>) in: schemeunit
main.ss:14:3: compile: unbound identifier in module in: hash-ref!

Is my mzscheme now new enough?
$ mzscheme -v
Welcome to MzScheme v4.1.4.3 [3m], Copyright (c) 2004-2009 PLT Scheme Inc.