To be bit more specific, you're missing enUS language pack.
At the link which jeger gave you, you can chose which language packs you wan't to download.
Make sure to download every file form the language which you intend to use as your WoW language.
Notify us in case there's any further issues.
If both teams share the same ip, then it should be a valid wintrade, & both teams should be banned,
If the enemy team queues and leaves & feeds the rate, it should be removed & the leaver team should be banned.
To all which are asking for the http://www.db.pandawow.me?item=112326/warforged-nightmare mount to be added.
It won't be added because on official it was added at the pre-patch which came after 5.4.8 (But the expansion was still Pandaria)
And Pandawow is core 5.4.7 therefore http://www.db.pandawow.me?item=112326/warforged-nightmare is not in the database & can't be added.
Have you tried changing the difficulty?
From normal to heroic, and same goes for the dungeon mode Hc / Nm (challenge mode will make your istance empty)
Greetings!
After you do the starting quests which involves talking with the pets,
You need to go to your class trainer & continue the quest line from there.
You're talking about something which happened long time ago while he didn't use it nor have it, meanwhile this happened recently, get real.
Closing the thread until GM further notices it to prevent it from being flooded & spammed.