You need to look at your NAT design, I would use something like:-

Global (outside) 1 interface

NAT (inside) 1 x.x.x.x y.y.y.y

NAT (DMZ) 1 w.w.w.w z.z.z.z

nat (inside) 0 access-list no-nat

nat (dmz) 0 access-list no-nat

access-list no-nat permit ip x.x.x.x y.y.y.y w.w.w.w z.z.z.z

access-list no-nat permit ip w.w.w.w z.z.z.z x.x.x.x y.y.y.y

x.x.x.x = Inside IP subnet

y.y.y.y = Subnet mask

w.w.w.w = DMZ IP Subnet

z.z.z.z = Subnet mask

The above will NAT the Inside to the outside using the firewall outside IP address.

It will nat the DMZ to the outside using the firewall outside IP address.

It will NOT nat the Inside to the DMZ

It will NOT nat the DMZ to the Inside

Is there a specific reason why you need to NAT from inside to dmz and dmz to inside?

HTH>