[plt-scheme] Installing .plt files

I've tried to install under plt the testsuite schemeunit lunching the 
command:

setup-plt schemeunit-1.2.plt

but there is the following error:

setup-plt: Compiling .zos for schemeunit at 
/usr/local/plt/collects/schemeunit
load-handler: expected a `module' declaration for `example' in 
"/usr/local/plt/collects/schemeunit/example.ss", but found something else
setup-plt: No more .zos for SchemeUnit Documentation at 
/usr/local/plt/collects/doc/schemeunit
setup-plt: Done setting up
setup-plt:
setup-plt: Error during Compiling .zos for schemeunit 
(/usr/local/plt/collects/schemeunit)
setup-plt:   load-handler: expected a `module' declaration for `example' 
in "/usr/local/plt/collects/schemeunit/example.ss", but found something else

The problem is that to install any library (es. schemeunit) under plt it 
must be defined as a module?
The only things I can do now without modifying schemeunit is to load it 
from my code?

Thanks.

Giannandrea