yum failed

[laiyhman]

Hello.

i'm a newbie....
When i issue the "yum" command(eg . yum search xxx)
i get the following error :

Searching Packages:
Setting up repositories
Cannot find a valid baseurl for repo: update
Error: Cannot find a valid baseurl for repo: update

but this only happend for certain user...for example if i login as root i will get that error when i "yum"....but when i use some other certain user then it is ok...can anyone tell me why is this happen?

thanks.