[racket] problems running moby from source

Hi,

I've installed moby from git and am following steps 5.3 and 5.4 from the documentation.
However, I get the following errors:


$ ./bootstrap-js-compiler.ss 
./bootstrap-js-compiler.ss: line 3: syntax error near unexpected token `only-in'
./bootstrap-js-compiler.ss: line 3: `(require (only-in scheme/list empty? empty first rest)'

$ cd ../examples/
$ mred ../src/moby.ss falling-ball.ss
/Users/.../Documents/racket/moby/moby/src/compiler/lang.ss:10:9: module: identifier already imported from: scheme/contract at: -> in: lang/htdp-advanced

=== context ===
standard-module-name-resolver


Could anyone perhaps give me a hint what I'm missing / doing wrong here?
I have racket 5.0.1 installed.

Thanks a lot in advance
Sigrid