Compress JS with JSBuilder (sencha)

Question

I want to compress my javascript/sencha touch app code with jsbuilder from sencha. I created a jsb3 file by hand and was able to generate a script file. But the deployment version is not getting compressed or obfuscated, even though I specified "compress": true in the JSON.

the error is

...
  * Compress and obfuscate appName.js...
rsync: -: unknown option
rsync error: syntax or usage error (code 1) at main.c(1455) [client=3.0.9]
java.io.FileNotFoundException: /Users/NAME/PATH/TO/APP/www/nameOfBuildJSFile.js-temp-882015127581.6014 (No such file or directory)
        at java.io.FileInputStream.open(Native Method)
        at java.io.FileInputStream.<init>(FileInputStream.java:120)
        at java.io.FileInputStream.<init>(FileInputStream.java:79)
        at com.yahoo.platform.yui.compressor.YUICompressor.main(YUICompressor.java:92)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.yahoo.platform.yui.compressor.Bootstrap.main(Bootstrap.java:20)

what am I doing wrong?