After I upgraded to Unity 4.7 I got a couple of errors "DefaultAsset does not exist" (attached snapshot of console).
I added: || UNITY_4_7 at the end of the #if condition, in lines 663 and 802 of tk2dSpriteCollectionEditorPopup.cs, and the errors went away.
However, I didn't look deep into this, and I don't know if this breaks anything. So, is this fix OK?
Thanks