I had this error as well, but can only confirm for pugilist 15 under JP client.
When I reset client to EN, the quest progressed okay.

World name: Sargatanas
Character name: Arche Koeln
Class/Level: Pugilist 15 class quest (but level 17)
Area and coordinates: Solo part of class quest - Central Thanalan, X16 Y20 http://i.imgur.com/g3XkczZ.jpg
Name of NPC: "Destination"
Quest name: "The Spirit is Willing"
Steps:
Each time I have done this it wont work. I will go through the entire quest till I get to the instance parts where I have to fight something solo. I will go up to the area click on it to start the lvl sync will come up and I will hit accept. Then I will get a message that says "A system error occurred during event movement" and then nothing will happen.
The same.