Mounting and dismounting the chocobo was easy on a 1900MB RAM server, now I've upgraded to 6GB server and my chocobos are now buggy, I can't dismount them.
Also getting the message of "moved to quickly"

You should always be able to dismount chocobos discounting when they are flying, I may have fixed the bug related to this already though. (I remember working on dismounting a while back..)