Randomly falling through the floor

Hello guys/girls, I'm just curious I am relatively new to the server (4months or so) whilst questing the other day with a friend, he was experiencing some issues, the issue is that he just kept falling through the floor... We tried multiple things and could not fix the issue, I did write a in game ticket but haven't had a response, I had a quick look on the forums too, couldn't find anything of the sort, all I want to know is, is this fixable somehow? As we love the server/realm lorderon being blizzlike, and would like to continue questing...

Thanks, Jaypwnzz.

This happens often on Frostwolf realm too. They have problems with their vmaps.
Sometimes it's get fixed by removing your cache.

Thanks for replying... Unfortunately multiple cache and wtf deletes did not fix the issue �� Can any gm shed some light on this?!?!