Symptom:
Not able to remove host name from running configurations, error message is generated when command is entered with (.) before the ip address.

Conditions:
Issue is seen on ME3600 switch running 154-1.S code.

Switch(config)#ip host www.abc.com. 1.2.3.4 <<<< error generate since not entered in proper format
No such hostname
Switch(config)#ip host www.xyz.com  2.3.4.5  <<<<<< Command accepted since it was entered in correct format.
Switch(config)#
Above commands will show up in the running configurations.
Switch(config)#do sh run | in ip host 
ip host www.abc.com. 1.2.3.4
ip host www.xyz.com 2.3.4.5
Switch(config)#

Command do not get removed from running configurations:
Switch(config)#no ip host www.abc.com. 1.2.3.4 <<<<< error was generated when tried removing host name
No such hostname
Switch(config)#no ip host www.xyz.com  2.3.4.5 <<<<< entry was removed successfully
Switch(config)#
Switch(config)#do sh run | in ip host
ip host www.abc.com. 1.2.3.4   <<<<<<  didn't get removed
Switch(config)#
Switch(config)#do sh host
Name lookup view: Global
Default domain is not set
Name/address lookup uses domain service
Name servers are 171.70.168.183, 171.68.226.120

Codes: UN - unknown, EX - expired, OK - OK, ?? - revalidate
       temp - temporary, perm - permanent
       NA - Not Applicable None - Not defined

Host                      Port  Flags      Age Type   Address(es)
www.abc.com.              None  (perm, OK)  0   IP    1.2.3.4