I've learnt something new today, and I wish to jot it down, in case I will forget this later. (I'm sure I will forget. :p)
My colleague reminded us to update the virus definition today, but I was having problem in updating it.
Then, my colleague helped me to solve the problem.
1) re-register the ole32.dll in C:\Windows\System32 folder.
2) Start the McAfee Framework Service.
a. Go to Control Panel --> Administration Tools --> Services
b. Look for McAfee Framework Service, right click and select "Start".