If they're 120fps RAWs, use
avi2tc first to take out all (or nearly all) the dummy frames that it has, then use VirtualDubMod to cut the clips away like Kariudo said.
'FFDS' is ffdshow's signal marker, which seems to me as if the footage is the standard DivX or XviD but being decoded with ffdshow, since I don't know of too many people that use ffdshow itself to encode stuff for distribution.
If VDub comes up with a warning that says it can't use DirectShow filters, uninstall ffdshow, go to
http://x264.nl/, download one of the ffdshow builds there (it depends on your processor and whether it can support only SSE or SSE and SSE2), and make sure that when you install the new one that you also enable the VFW interface. You'll need to manually configure the VFW interface to enable using it to open video files in VDub, but that's not hard since the configuration dialog for the VFW is available through the Programs menu or in VDub's Compression... area - you'll want to look at the tab that says 'Decoders' and switch things pertaining to DivX and XviD to libavcodec.