Loading interlaced video using FFVideoSource

[WIRLYWIRLYPOOL]

I ripped a BD of mine, extracted the tracks, and muxed it into a matroska...Now im trying to load it using FFVideoSource...However, every time i load it i get this error...

http://i46.tinypic.com/5777d.png

(Im loading the Avisynth script in MPC-HC to see how it looks, not encoding or anything)

Heres my script so far...

LoadPlugin("C:\Program Files (x86)\AviSynth 2.5\plugins\ffms2.dll")
FFVideoSource("F:\ENCODING\MKV\RAW.mkv")

Im just trying to load the interlaced video at this point...my goal is to output it as a progressive video, but im still not sure how i will go about doing that...im basically new to avisynth so i dont know much...some of the terms confuse me x(

Also, if anyone can link me to where i can find out how to output as a progressive video i'd greatly appreciate it :D

Any help would GREATLY be appreciated...ive been stuck on this for weeks and cant get through...

**EDIT***
Tried using bob () and it loads now...script looks like...

LoadPlugin("C:\Program Files (x86)\AviSynth 2.5\plugins\ffms2.dll")
DirectShowSource("F:\ENCODING\MKV\RAW.mkv")
bob()

But im thinking interlaced --> progressive isnt gonna be that easy...