I used Forward function with the original offer email, add my MyPoints account details and the offer code from the invitation, attached a pdf file of the WM receipt and the invitation, sent it to the address as instructed.

Somehow the reply went to my secondary email address registered with Yahoo. Dont know why. But here is the response:

Thank you for contacting MyPoints Member Services.

Please be informed that the points will be credited to your account within 1 to 2 weeks.

We apologize for any inconvenience and thank you for your understanding.

So the response is overnight, but the points may take weeks to show up on this go round. The points posted really quickly on the 1st go round based on posts here. I hope this time it would not take longer than indicated. Unfortunately I did not partake the 1st round - wasn't paying any attention but now I view it as UA miles earning opp so I am motivated.