http://mykbit.blogspot.com/2010/03/error-while-importing-option-6-while.html

To move DHCP from one server (2003/2008) to another you can use the following steps

1. At the command prompt type netsh dhcp server export C:\dhcpdata.txt all , and then press ENTER.

Note: You must have local administrator permissions to export/import the data.

Configure the DHCP server service on the server that is running Windows Server 2008

1. Add DHCP Server Role
2. Make sure to Authorize DHCP while installing the Role.

Import the DHCP database

1. Copy the exported DHCP database file to the local hard disk of the Windows Server 2008-based computer.
2. At the command prompt, type netsh dhcp server import c:\dhcpdata.txt all and press ENTER

If might receive the following error

“Error while importing option “6.” “This option conflicts with the existing option “” An Internal Error Occurred.”

It is because by default when you install DHCP Server Role, it puts the following entries in Server Options.

006 DNS Server
015 DNS Domain Name

To fix the Error –> Just delete the above two entries from Server options and Run the Import DHCP database command again