Problem when pre-composing masked layer

Ok, i am having a problem when masking a Twixtored layer.

this is what happens:

i have the original footage in a comp, i used twixtor to slow it down to 3% speed

Seen here: http://prntscr.com/zbicc

I Then pre composed that slowed down layer into a comp of it's own and masked around that parts i wanted and named this comp "masked comp 1"

Seen here: http://prntscr.com/zbitw

and here: http://prntscr.com/zbiyc

i then precomposed the masked layer into another comp called "sky replacement" and this is when i hit the problem, it dosn't show up, it just gives me a black screen.

Seen here: http://prntscr.com/zbj9n

and here: http://prntscr.com/zbjcn

I tried rendering out "Masked comp 1" and "sky replacement" and with both it just renders a black screen, but if i render the Twixtored comp that renders fine. So i think it has somthing to do with the mask but i can't figure it out.

Please help.