Действительно, максимальный размер фала для fat32 - 4gb.
Но не стоит радоваться ;-)

http://support.microsoft.com/default.aspx?scid=kb;en-us;193656

SYMPTOMS
When you try to play a large audio-video interleave (AVI) file, you may receive the following error message:
The file format is invalid.
CAUSE
This error message can occur when you try to play an AVI file that is larger than 2 gigabytes (GB) in size. Limitations exist with Microsoft Video for Windows solutions that limit AVI files to the same maximum file size as the FAT16 file system, which is 2 GB minus 1 byte.

On computers using the FAT32 file system, the maximum file size is 4 GB minus 2 bytes, which is larger than Video for Windows is designed to handle. AVI files created by Video for Windows that exceed 2 GB in size appear invalid or damaged to AVI file players.
RESOLUTION
When you are using Video for Windows-based programs, limit the size of AVI files that you create to less than 2 GB.
MORE INFORMATION
Programs using Microsoft DirectShow can create AVI files that exceed 2 GB in size on computers using the FAT32 or NTFS file system.

те использовать можете, но это криво. Поэтому практически во всех FAQ по видеомонтажу для Windows систем рекомендуется использовать ntfs.
Если согласны, то я окультурю это.

PS а что у вас со звуком случилось? Первый раз вижу 32000Hz