A problem with Matlab on Unix

I'm running Matlab on Unix and want to change the keyboard shortcuts to be as in Windows. However, when I try to open Preferences -> Keyboard -> Shortcuts, it does not load and it gives the following error:

PrefsDialog: unable to find class com.mathworks.mlwidgets.prefs.binding.KeyboardShortcutsPrefPanel, with method createPrefsPanel. java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.mathworks.mlwidgets.prefs.PrefsPanelWrapper.createPanel(PrefsPanelWrapper.java:137) at com.mathworks.mlwidgets.prefs.PrefsPanelWrapper.getComponent(PrefsPanelWrapper.java:94) ...

There was a similar question on http://www.mathworks.com/matlabcentral/answers/98454 but the answer was not helpful to me since the only classpath.txt I found was $MATLABROOT\toolbox\local\classpath.txt.

Thanks