Hi Bala,
I see that JDavis had already pointed out in another thread (https://www-secure.symantec.com/connect/forums/how-add-nic-drivers-symantecbrightmailgatewayosrestore803-11linuxintiso-image#comment-3368321) that installation on dell workstation is not supported. Please use the supported hardware/software to avoid running into issues that support is not able to assist with.
Since you want to use Brightmail Gateway Software on your own hardware, as JDavis suggested, you should deploy it under VMWare ESX/ESXi. Please see the topic titled "Symantec Brightmail Gateway Virtual Edition" in the Symantec Brightmail Gateway 8.0 Installation Guide available here for more details:
ftp://ftp.entsupport.symantec.com/pub/support/documentation/sbg_installation_guide.pdf
Thanks for your interest in Symantec Products.
Regards,
Adnan