How to export a DNxHD file in AME

Im having a bit of a problem. I shot a music video, edited on Premiere, footage was 1080p(24fps) on 60d. I exported the vid using QuickTime and dnxhd as the codec. This gave me about a 6gb file for a 5 minute video. I then put that same file back into adobe media encoder to reexport to h.264, YouTube preset. Thats when the problem starts. While it is encoding something weird happens with the pixels. I see specks of green and yellow that show up on the video when it is done encoding. I tried resizing it to 720p but i got the same result. Can anyone tell me what im doing wrong?

Also is it normal for a 5 minute vid to be around 6gb when exported to dnxhd?

 

Export settings: QuickTime to DNxHD codec, re-export h.264 to YouTube preset(target bit rate 10, max 40)

 

Hp pavillion, i5 processor, 6gb of ram, ati radeon graphics

 

Any help is appreciated, thanks

via Adobe Community : Popular Discussions – Adobe Premiere Forums http://forums.adobe.com/thread/1117995