It has AC3 sound, so download Media Player Classic, which has internal AC3 decoder, or use ffdshow which has also AC3 decoder or use standalone AC3 filter.
Anyway that espise-xvid-graveyard-subs.rar doesn't include .idx file.
I'm trying to download ed2k:
The.Graveyard.2006.DVDRip.XviD-ESPiSE-subs.rar [1.17 Mb] [
Stats]
which is slightly larger, so might contain .idx file.