This is more complicated than it should be, but this has been sorted in the next release.
Do you have the tk2dUIAudioManager on the same object?
Whats happening is
tk2dUIManager -> camera1
when you reload, camera1 gets destroyed and recreated, but since uimanager is not destroyed, its still pointing to camera1.
The easiest way around this right now, is to simply assign camera1 to uimanager immediately after loading.