deployment.system.config is the URL to the system (enterprise-wide) deployment.properties file. This property can be used by system administrators to centrally administer or "lock-down" user-specific configuration settings. For local files, use the file protocol in the URL, for example, file:///C:/Windows/Sun/Java/Deployment/deployment.properties.
Source: http://docs.oracle.com/javase/7/docs/technotes/guides/jweb/jcp/properties.html
Note the forward slashes (I had this issue before).