According to this link:
http://www.symantec.com/norton/internet-security
In the 'System Requirements' section it says:
Browser support for Vulnerability Protection and Phishing Protection
- Microsoft Internet Explorer® 6.0 or higher (32-bit only) ***
- Mozilla Firefox® 3.0 and later ***
This means Phishing and Vulnerability protection won't work on a 64-Bit system, I need more information as one of my laptops is 64Bit and Phishing and Vulnerability protection is critical.