RPM REMOVE ERROR

[rpm akshbroadband com]

HI,

I have problem when i remove some package from my redhat
linux PC that not installed it give the error

[root devendra
~]# rpm -e postfix
error: package postfix is not installed

i also try this :-

[root devendra ~]# rpm -e postfix
2>&1 > /dev/null
error: package postfix is not installed

i want that the commnad rpm -e don't give any error.
if
package installed or not . how i do this 

Regards
Devendra