problem export objects from clean scene

[andrasbort]

Hi,
i cleaned an old scene that i used for rendering with cycles. I deleted all material but i kept all the slot.
When i export object Blender shows me an error (to watch file attached).
Then i deleted all objects one by one for exported, but without results.
Only if i delete all objects and i create new objects then Blender export without problems.

What could be the problem?

Thanks

[blanchg]

Get the latest exporter or delete empty material slots

[andrasbort]

Ok, I misunderstood a tutorial!

Thanks!