OP had a link to the promo. To repeat, http://www.united.com/page/article/1...SA04_moremiles

Read the fine print:
* Offer valid for qualifying travel ticketed and completed between November 10, 2006 and January 31, 2007...
* Registration prior to travel and before December 31, 2006 is required. You may register at united.com/offer/MPDG26
* Bonus miles will be deposited four to six weeks after the end of the promotion period.

Therefore, the promotion end when January does. If earned, your 25K miles should show up in early March.
And the code is MPDG26.

and for aau, the key line is...

Roundtrip is required. A roundtrip is defined as travel from an origin city to a destination city with return travel beginning in the outbound destination city back to the first origin city... others may know better, but... probably.
Not because of alternate cities, but. Check the fare rules and near the bottom there's something like this.

"NOTE - THE CITY PAIRS BELOW ARE CONSIDERED THE SAME POINT- BWI-WAS FLL-MIA FLL-PBI MIA-PBI BUR-LAX BUR-ONT BUR-SNA LAX-ONT LAX-SNA ONT-SNA OAK-SFO OAK-SJC SFO-SJC EWR-HVN EWR-ISP EWR-NYC EWR-HPN HVN-ISP HVN-NYC HVN-HPN ISP-NYC ISP-HPN NYC-HPN"

To me that sounds like SFO-XXX-OAK is a round trip, not an open jaw... but are they being more strict in the promo? I wouldn't think so.