Server Authorization error on Playready License Server

Server Authorization error on Playready License Server

I am getting following exception in Playready license server whenever my
silverlight player tries to play the PR protected streams
Internal service error.\r\nClient record locator =
3a7d80c8-530a-45b0-86d4-a00a2043b4bc \r\n\r\n
Microsoft.Media.Drm.RMServerException: Caught an exception while trying to
load the configured handler type \"ServerAuthorization\". --->
System.Reflection.TargetInvocationException: Exception has been thrown by
the target of an invocation. ---> System.NullReferenceException: Object
reference not set to an instance of an object. at
ServerAuthorization..ctor() --- End of inner exception stack trace --- at
System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean
publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle&
ctor, Boolean& bNeedSecurityCheck) at
System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean
fillCache) at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly,
Boolean skipVisibilityChecks, Boolean fillCache) at
System.Activator.CreateInstance(Type type, Boolean nonPublic) at
Microsoft.Media.Drm.HandlerLoader.GetHandler(Type handlerType
Please let me know if anybody has faced the same error and found a solution.
Thanks,
Tarun Singhal