C# - Threading Problem With Monitor.Wait () And Monitor.Pulse ()?

I have a producer-consumer scenario in ASP.NET. I designed a Producer class, a Consumer class and a class for holding the shared objects and responsible for communication between Producer and Consumer, lets call it Mediator. Because I fork the execution path at start-up (in parent object) and one thread would call Producer.Start() and another thread calls Consumer.Start(), I need to pass a reference of Mediator to both Producer and Consumer (via Constructor). Mediator is a smart class which will optimize many things like length of it's inner queue but for now consider it as a circular blocking queue. Producer would enqueues new objects to Mediator until the queue gets full and then Producer would block. Consumer dequeues objects from Mediator until there's nothing in the queue. For signaling between threads, I implemented two methods in Mediator class: Wait() and Pulse(). The code is something like this:

Class Mediator
{
private object _locker = new object();[code]....

Inside Mediator I use this.Pulse() every time something is Enqueued or Dequeued so waiting threads would be signaled and continue their work.But I encounter deadlocks and because I have never used this kind of design for signaling threads, I'm not sure if something is wrong with the design or I'm doing something wrong elsewhere ?