%static entry in use cannot remove

is this your problem ?

router(config)#no ip nat inside source static tcp 10.0.0.100 5555 interface FastEthernet0 5555 
router(config)#%static entry in use cannot remove

SOLUTION

interface FastEthernet0 - WAN

router#configure
router(config)#interface FastEthernet0 
router(config-if)#no ip nat outside
router(config-if)#exit 
router(config)#

interface FastEthernet1 - LAN

router#configure
router(config)#interface FastEthernet1
router(config-if)#no ip nat inside
router(config-if)#exit 
router(config)#exit

next step 

router#clear ip nat translation forced
router#configure
router(config)#no ip nat inside source static tcp 10.0.0.100 5555 interface FastEthernet0 5555 
router(config)#exit
router(config)#interface FastEthernet0
router(config-if)#ip nat outside
router(config)#exit
router(config)#interface FastEthernet1
router(config-if)#ip nat inside
router(config)#wri