[Netfabb Problem]

Hallo,

I´m from Germany so I hope you can forgive me because my English is not that good.

I work with Netfabb Basic for some time,but this time my model seems to have a bigger mistake, or maybe it´s also a Netfabb Problem.

If I repair my modell (.stl --> automatic repair) there are always those red surfaces like in the picture.

What do I need to do ?

Thanks for your help.