Imovie Optimizing makes video turn green!

Please help !
I am working on Imovie 9.09 after downgrading from Imovie 10 due to exporting issues.

But I am having much difficulty with some Mp4 files ..

I have "Optimizing" unchecked but the program still demands the videos to be optimized.

I have Mp4 running and they play fine on VLC / Quicktime etc.
But every time I import certain video that optimize they turn green but audio plays. The picture preview shows up but still no video at all!
This is so frustrating, i've tried changing frame rates but this does nothing!
What do you think I should do, keep using 9.09 or go back to Imovie 10.

Tried looking up this issue but have not found an acceptable answer!

I have been experiencing a lot of bugs / glitches in Imovie 9.09 but at least it exports faster than Imovie 10.

Any help would be much appreciated

Running OSX El Capitan on a Macbook 13" pro 2010 model

Thanks