Unknown message when I open a p3d

[Chris Young 3]

When I open some of my p3d's, I get this message :

I don't know why (I've used o2 for some time without ever encoutering this), and I neither know what it is for and what I should answer.

Maybe someone can help ?

[Sennacherib 0]

yeah, i have the same window, for one of my models, but in game all work fine; so you can ignore it.

[Chris Young 3]

Ok, then I'll go on with it. Quite surprising however.

[Sennacherib 0]

yeah, i don't know why we have that. if you want to know the reason, you could ask to Nephilim, she is an oxygen master