Creating a Totally new Monster

So I found the Perfect world band, and I got them working perfect exactly what I wanted thm to do, but whenever I try and make them into pets or make them Mobs it gives me a client version too low "And I know its the elements doing this" I can make monsters already in the game into pets but these just refuse to be nice to me=/ any ideas on why it's causing my maps to crash? Never had elements cause this "And I know it elements because if I go back to my older ones it starts up without a problem" ......... Somebody just shoot me Please D:

Okay, I fixed my Problem. Taking a break, getting some sleep and a nice cup of tea, I came back re-looked at my problem and realised how much of an idiot I am. So, 343 feel free to lock and or delete this. I'm sorry about the spam guys some things I guess I need to express take a break and come back and look at. Oh well... Igor is going back to work :wave goodbye: