[flexcoders] TypeError: Error #1009 using modules

[bcncgn3]

I`m using modules in my application and I get always the following
error message: "TypeError: Error #1009: Cannot access a property or
method of a null object reference." when the second module is loaded
and his initialize-method is invoked. The first module works fine, but
despite which is the second module it fails loading with always the
same error message. 
Someone had the same experience? Is there a solution?