That is utterly unrelated to 32bit vs. 64bit. If the files don't import, then they are simply encoded with unsuitable options. AE should handle natively captured DVCPror from Premiere just fine as it should handle Quicktime DVCPro. If the clips are captured with other tools, you will have to provide more detailed info and possibly a sample clip. If you artificially encode it to DVCPro, then the logical thing would be to not use that option. Kinda defeats the purpose, anyway - AE will decompress it again and you only add an unnecessary step of compression.