Well the problem you're having doesn't have anything to do with file size. I can import a 1080p lossless avi without any problems in After Effects and the file size of that is a few hundred GB. Does the VOB/Mpeg2 file you are importing have the AC3 audio track intact? If so then that will cause you problems. You need to demux the Vob file into the separate streams and just import the video (sometimes you will need to remux it to an mpeg2 video only file first because after effects can be a bit picky with m2v files).

From the look of your screengrab it looks like the header of the Mpeg2 file could be screwed up so demuxing then remuxing would rewrite the header. I take it you are working with an NTSC source right? Have you removed the 2:3 pulldown on the video before converting it to a MOV? Plus i wouldn't recommend using a DV codec for your project, especially if you are going to be doing multiple renders (colour correction etc). You will lose quality and it isn't the best codec to start off with. Try using a lossless codec like lagarith (unfortunately not available for mac by the looks of it) or huffYUV (although premier does have a few issues with that codec). Your best bet would be to google a lossless codec for the mac, but be warned, you will need a lot of hard drive space ( about 100gb for each render of a DVD source). But this way you won't lose any quality on each generation of the encode. Plus, if you are doing colour correction, then a lossless codec is a must. The last thing you want is to introduce extra video noise or artefacts caused by a lossy codec like DV

Unfortunately you are using a mac and i have no knowledge on what programs you can use to do all of this