[Yum] ImportError: No Module named yum

[Steven Smith]

Hello,
	I am a newbie to linux trying to get Yum to work on my redhat
enterprise Linux ES 3 system.  I download yum-2.2.0-1.noarch.rpm and
installed it using the command 'rpm -Uvh yum-2.2.0-1.noarch.rpm'.
	The output from the rpm command looked like it completed successfully. 
I edited the yum.conf file to add the following lines 
[xcyb-stable]
name=Fedora Core 3 ( xcyborg / stable )
baseurl=http://rpms.xcyb.org/fedora/3/stable/

	After reading the yum.conf man file I added enabled=1 to the yum.conf file.

Anyway, when I run yum it gives me the following error;
  Traceback (most recent call last):
  File "/usr/bin/yum", line 6, in ?
    import yummain
  File "/usr/share/yum-cli/yummain.py", line 23, in ?
    import yum
ImportError: No module named yum

How do I resolve this error?

Thanks in advance for your time...Steven