Coz, the explorer crash causes due to a various reasons. One of the most frequent cause is it fails to handle the filetype containing in a particular folder, and when the user is trying to access that folder, explorer crashes. As in your case it is occurring in a particular folder only.
Moreover, among the filetypes, video files are the most vulnerable, coz we use third party codecs to handle those, to generate thumbnails etc. So here comes the next question:
What is the codec pack you use? Klite? Media player classic? Or anything else?