The Missing Vanguard bug

Im having problems with the Missing Vanguard quest. I went to the tattered Vanguard clothing and then talked to the Vanguard helmet to do the "Against the Charr" mission. When I was done I looked at my quest log and it says I still need to "Search for the Vanguard in the Charr homelands". It says I've completed "Speaking to Gwen in the Hall of Monuments" and "Traveling to Longeye's Ledge to search for clues about the vanguard". Any ideas?

The next quest can be found here http://wiki.guildwars.com/wiki/The_Dawn_of_Rebellion

You need to release the rest of Pyre's charr band so they can help you rescue the Vanguard prisoners.