Fix , just type in console completequest DLC2RR01 & ENTER It worked for me !

Ehm, what?

you really should be careful using Console Commands.. they are not Cheat Codes or toys, they are debugging tools the devs left to make it easier for Mod Makers to bug test their mods...

Here is the link to that quest on UESP Wiki: http://www.uesp.net/wiki/Dragonborn:March_of_the_Dead. The quest naturally ends when you do the final task of informing Captain Veleth (I am avoiding spoilers here). There is no reason to use commands to do this.