Cannot invoke "com.heliosapm.utils.jmx.builtins.BuiltIn.execute" because "this.builtIn" is null

When I am trying to connect to a JVM process I get the following error:

```
-bash-4.2$ java -jar jmxlocal-1.0.jar  -jmxurl service:jmx:attach:///768
FAILED.:java.lang.NullPointerException: Cannot invoke "com.heliosapm.utils.jmx.builtins.BuiltIn.execute(javax.management.MBeanServerConnection, String[])" because "this.builtIn" is null
```

any ideas what could go wrong? Thanks!