Can't Drag files from the project bin to the timeline

Hey All,

I'm trying to drag images from the project bin to the timeline and it's not allowing me to.

I also can't drag to reorder the layers in the timeline or drag to rearrange the order of the files in the project bin... so pretty much I am not being allowed to drag anyting in aftereffects.

Does anyone know why this is / how to fix it?

Thanks,

Dan