centos 5.3: How to install "rpm"

Hi,
1) I have a machine A which has a Centos 5.3 operating system
2) I want to practise to install "RPM" in this machine
3) I try to get the "samba" rpm as follows:
[root@localhost~]#rpm qa|grep -i"samba"

4) It gets the results like this:
samba-client-3.0.33-3.7.el5
system-config-samba-1.2.41-3.el5
samba-3.0.33-3.7.el5
samba-common-3.0.33-3.7.el5

5) Now, i try to practise to install "rpm" as follows:
[root@localhost~]#rpm -ivh samba-client-3.0.33-7.7.el5
The Result is:
error: open of samba-client-3.0.33-3.7.el5 failed: no such file or directory

6) I try another one, like this:
[root@localhost~]#rpm -ivh system-config-samba-1.2.41-3.el5
The Result is:
error: open of system-config-samba-1.2.41-3.el5 failed: no such file or directory

7) I am not sure which one is WRONG HERE
8) My goal: I want to be able to install an "RPM" (any "RPM"; in this case, i select "samba")
9) My question:
First: Would you show me "what wrong here"?
Second: Please "direct" or "navigate" me to install an "RPM" correctly (any "rpm")
10) Thank you

tjie