[plt-scheme] Error using sandbox

I've changed the code to the following, but still get an error:

(parameterize ([current-directory (string->path
"/Users/noel/programming/schematics/schemeunit/branches/v3/")])(make-module-evaluator
'(module m scheme/base (require "test.ss") (void)) #:allow-read
'(("test.ss"))))
cleanse-path: file access denied
(/Users/noel/programming/schematics/schemeunit/branches/v3/test.ss
exists)

 === context ===
/usr/local/plt/collects/scheme/sandbox.ss:215:9
/usr/local/plt/collects/scheme/sandbox.ss:199:0: call-with-limits
/usr/local/plt/collects/scheme/sandbox.ss:371:0: evaluate-program
/usr/local/plt/collects/scheme/sandbox.ss:443:2: user-process

I don't understand why I can't access a file I have explicitly said to
allow.  Do I need to use a full path?

Thanks,
Noel