Server 2003 DNS Cache Issue

Hi All,

I have recently setup multiple intranet websites using virtual hosting and I had setup the correct A records for each site in the DNS in Server 2003. The server resolves each site correctly for awhile and then stops. I clear the DNS cache on each server and resolution problem goes away for a time and comes back. Can any of you please help me figure out what is causing this to happen or how to fix it?

Thank you all in advance.