I installed MRL about a week ago. Everything worked fine in virtual mode but as soon as I hooked up the hardware (InMoov hand and arm)  MRL would crash during startup.  After about 4-5 days on and off  of troubleshooting I went on-line and spoke to GroG and uploaded a couple of log files.  He immediately determined it was a serial communications error caused by the jssc-2.8.0.jar and suggested I replace it with version jssc-2.9.2.jar  (here it is: https://github.com/java-native/jssc/releases).