If all three groups are weighted evenly, Pres. Bush leads Kerry 49-45%. Interesting.
Yeah, I checked what the equal weight groups would lead to given equal the GOP, DIM and Independent breakdowns and I came to the same result as you. I then calculated the weights required to get the LATimes breakdowns the Bush respondents get an 85.1% weight, the Nader+Undecided respondents getting a 93.75% weight and the Dims get a 105.9% weight.
When I weighted the GOP as 45.2%, DIM as 45.5% and Independents as the rest, 9.3%, I get the Bush respondents are now getting an 85.1% weight. And Bush should by the internals in the poll lead 49.2 to 45.2. The Dims are getting a 106.2 weight.
I wonder what the 2002 breakdown was. That would give some interesting national figures.