Effect maker: Create new effect gives error dialog

Steps to reproduce:

1. Click 'File' -> 'New File'
2. Select 'Effects' from the list
3. Click 'Choose..'
4. Give filename to the effect e.g. 'MyEffect'
5. Click 'Continue'
6. Click 'Done' on the next view

Expected behaviour: MyEffect effect is created and added to Assets. Asset library opens and shows the recently created effect

Actually behavior: First you get this error

And then you get this one: