DNS server able to resolve but unable to query root servers

[Ashwin Kotian]

I'm having a problem with Split-DNS server running on a single machine 
(Redhat Linux 7.1) where the external server is able to resolve names 
for domains it is authoritative for but is unable to query any other 
root servers. If I remove the forwarder directive for the internal 
servers & use internal server as my primary DNS server, it can easily 
resolve & query all external domain names.

If I try to use the query source directive for the external name server 
& provide it a query source IP address, I see the error " could not get 
query source dispatcher " & the name server is still unable to contact 
the other root name servers. I have the root.named file in the external 
name server directory & have the corresponding zone info in the 
named.conf file.

I fail to understand why the external name server is unable to talk to 
the root name server . Any suggestions/ideas is greatly appreciated.

Thanks,

Ashwiin.