Cisco Address translation

This following config is intended to translate any traffic with the source address of 172.20.49.10 (from the server) on TCP port 7500 to the following NUA (another server). When doing this it gets a duplicate address error on the console
Config Exerpt
x25 routing interface
serial 0/0 encapsulation x25
x25 address *********
x25 route 123 interface serial 0/0
translate tcp 172.20.49.10 port 7500 x25 123
any help welcome