GOM player not running video
I'd say it's an issue with GOM Player subtitle renderer. 

It's probably trying to open/read the subtitles but fails and this failure makes it impossible to play the video (it's probably a bug in GOM Player, since most player would just skip the subtitle and play the movie anyway). 

I'd suggest you try another player, VLC is fine, Perian works great with QuickTime or MPlayerX which is free on the Mac App Store. And they all play subtitles, also.