Had a lot of ‘fun’ enabling the RSA cards on our 3850’s. Once I got that going when I tried to remote in caused this error.
MCS v.3.6 initialized
Initializing RemoteDisk v2.2
Connected via socket: Socket[addr=/,port=2000,localport=18428]
java.lang.NullPointerException
at mcsClient.Row.isValid(Unknown Source)
at java.awt.Component.invalidateIfValid(Unknown Source)
at java.awt.Component.setLocale(Unknown Source)
at javax.swing.JComponent.(Unknown Source)
at javax.swing.JPanel.(Unknown Source)
at javax.swing.JPanel.(Unknown Source)
at javax.swing.JPanel.(Unknown Source)
at mcsClient.Row.(Unknown Source)
at mcsClient.Options.(Unknown Source)
at mcsClient.McsToolBar.(Unknown Source)
at mcsClient.McsClient.begin(Unknown Source)
at mcsClient.McsClient.init(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception: java.lang.NullPointerException

I eventually figured it out, more details on the adventure here http://mellerbeck.blogspot.com/2009/07/mcs-v36-initialized-java-error-ibm-rsa.html