Error Types

[Yiiim]

I could not figure out how to fix this type of error. Which mistake would lead to these errors? 

[AeroSoul]

It would be easier to help point out a mistake in your code if you actually supplied it.

From the error itself you can see that problematic is "Preview Queue Element" function, because it has a wrong type of input. 

With lack of code i can only guess it's because you either supply wrong or invalid "queue" input.

EDIT:

By wrong or invalid i mean either wiring straight queue constant to the input without initializing the queue itself or possibly overwriting an exiting queue with a default value (or some other common mistake)