WordPress MU

I have a hosting account at Justhost.com.
I need help with how to ADD WILD CARD DNS to the domain.
I'm using wordpress mu and anytime i create a blog i get this information INTERNAL SERVER ERROR.
I also want to find out if I can do that in my CPanel.
How do I locate the Virtual host file?
Thank you

Best bet is to ask your hosting support.

to my part

i had pb to get a wildcard on my dns zone

i used a free dns server because i did not wanted to get time on it

(just adding the wildcard on my virtual host using webmin)