I’ve getting the same Problem with 3.0.1 .
Everything works, except the SlideShow without (!) the “Picture aspect” checked. Everytime i check the Picture aspect it works fine, but without it, it won’t. I’ve searched the php for anything related, and also granted full access for the directory (reading/writing) to test it out. But nothing helped yet.
As Ralph I first came to an rights conclusion, but it don’t solved the Error message.
I think i need support on this.