Random errors/crash as nidhogg dies

Time: 12:43am (about) 2016/02/12 JST
Frequency: First time
World name: Behemoth
Character name: Mayoyama Nakata
Monster name: Nidhogg (The Aery)
Class/Level: DRG 60
Party or solo: Party
In-game time: unknown
Area and coordinates: The Aery, final boss room
Steps:
1. Participate in the Aery on DRG (60) with some FC friends (and 1 random healer), to complete the i170 relic quest
2. Kill final boss. the second the boss would have died (didn't see the death animation) my game froze, I receive the below windows errors and game exits.

https://www.dropbox.com/s/x46ywf0rl4...31.21.png?dl=0

3. Log back in to find that the game didnt register my kill of the final boss, forcing me to rerun the dungeon all over again to finish the relic quest

Never encountered this before


Laptop Model Name: Asus
Laptop Model Number: F555LJ

Gamepad Manufacturer: Elecom
Gamepad Model Name: Wireless