Eror to create Isolated Network in Org VDC Network

Hello mates,

Im trying to create an isolated network for a vAPP but I've recieve this strange error. I found some solutions "googleing" but nothing works for me.

Any idea? Im using vCloud Director 5.6.4 with ESXi 5.5 Update 3 and vShield 5.5.4.

I attach an image removing the sensible naming.

Thanks a lot