I was recently able to solve this by logging into the game via the PS3 (I was playing on PC) where I was able to target the snowman and progress with the quest. However, I will provide my specifications just in case. My guess is that its something minor installed incorrectly in my game.

Time: August 29, 2013 11:20-11:40pm EST
Frequency: All the time
World name: Hyperion
Character name: Ewan Gunther
NPC name: Snowman
Monster name: Irrelevant
Class/Level: Arcanist 39
Party or solo: Solo
In-game time: unsure
Area and coordinates: Coerthas Central Highlands X:26 Y:27
Steps: "Locate the source of the voice" where the steps I had to take to progress in the quest. I went to the target area marked in red on my map where I found the Snowman glowing, however, I was unable to target it and therefore unable to progress with the quest.

Connection Specs
- Type of internet connection/provider: DSL/Claro
- Modem maker/model number: Thomson

PC Specs
Operating system: Windows Vista Home Basic (6.0) 32bit
Processor: Intel(R) Core(TM)2Duo CPU E7200 @ 2.53GHz 2.5GHz
Memory: 4GB
DirectX 11
Graphics: ATI Radeon HD 5700 Series