You don't say which version you're using, but I had a similar problem indexing videos and found PCSM was freezing on one particular file (or group of files, I don't remember exactly). I think I changed the shared folders to only index one at a time to help me isolate the problem until I could identify and remove the file.
It's possible you'd be able to tell from the database itself how far the indexing gets before stopping. My thumbnails are stored under C:\Program Files\Samsung\SAMSUNG PC Share Manager\MediaRoot\HDD\Video. [MediaRoot is a hidden folder.]
How to disable PC Share Manager thumbnail creation when refreshing DB? I simply can't share my videos because of this.. the PC share manager hangs on the very first videos being treated. The only solution is to disable the thumbnail creation process or fix the software.. so what I can do?