If this is From a Retail DVD then it Should be Progressive because 99% of Movies are Shot on film Includeing this one..But you are right it does look interlaced and it looks Like Bad Field Blending...I allways get Better results Useing the "Smart Bob" Filter to deinterlace and the Line after the deinterlace in the AVS script add the Sharpen Filter, Just Put this in
Sharpen(0.75)
After the Bob deinterlace in the Script but before any Resizeing....Let us Know how it works out...Cheers

The Seperate Fields Filter is Simular to the "Smart Bob" filter accept that what the "Seperate Fields" filter does is Take one Field and throw the other one away so each Frame is one Field , The Smart Bob filter does the same thing accept it interpolates the Missing Field from the One that it keeps giveing a true Progressive Frame, it Does Produce a Slight Blurring which Most deinterlacers do but if you add the Sharpen filter it helps get rid of any Blurring and Produces a Better Quality Picture compared to most other deinterlacers....Cheers