Here is a transcript of the relevant portion of the TMZ interview, which lasted all of a minute.
TMZ: Do you think Sarah Palin should be our president in 2012?
Rivers: "I think Sarah Palin is an amazing woman, I think she represents everything a strong woman should be and she should go someplace like to another planet and show them and get out of our face."

TMZ: A lot of people in Tucson...a lot of the big media outlets are blaming Sarah Palin for the shootings.

Rivers: They're right.

TMZ: To blame Sarah for the shootings?

Rivers: They're right to blame Sarah for the shootings.  Go look at her website.  Go look at it.  This woman is encouraging sandbags (several words are lost in the crowd noise) blood libel because she's stupid and a threat.

TMZ: What does blood libel mean?

Rivers: Sarah Palin.

TMZ: (Laughs) Thank you Miss Rivers, you're awesome.
TMZ posted the interview on their site Sunday morning.   This morning, the other shoe dropped.

Early this afternoon, Rivers tweeted this series of remarks.
While @melrivers and I were promoting our new @wetv reality show, I made a joke about Sarah Palin that was picked up by @TMZ.

As a result, our appearance on the Fox News Channel tomorrow morning has been cancelled.

Outcome: DON'T PISS OFF SARAH PALIN. She’s apparently "very powerful," and is obviously still smarting from the end of her reality show.

I was cancelled from Fox for saying Palin is "stupid and a threat". Wait till I REALLY shock them with Aretha Franklin is a bit chubby!

I'm feeling very nostalgic right now. I was cancelled from a Fox show today. Ahhh.....the 80's really ARE back in style!!!
Rivers elaborated on her sitatuation for New York Magazine.
We’re here to promote our new reality show and we’re talking to everybody. And somewhere along the line, I must’ve said something about Sarah Palin, she should be on another planet, she’s stupid, and this morning it came down. We were ousted from Fox & Friends, I guess Fox & Former Friends. Our PR person was told specifically, because she asked why, it was because of the Sarah Palin remark, which they now are denying. This girl! We’ll take lie detector tests. It’s absolutely exactly what they said.
You read that right, Fox is denying that was the reason.  Here's what they told Joe Pompeo of Yahoo! News:
"Due to the volume of news topics tomorrow morning and a full show, our booker mistakenly canceled Joan's appearance instead of re-scheduling her for Friday's show," said executive producer Lauren Petterson in a statement Wednesday. "We're in the process of booking her on an upcoming show."
It seems that's not going to happen.  As the headline of the article on Popeater about the kerfuffle says Joan Rivers: FOX Can 'Go F**k Themselves' Over Sarah Palin Controversy.

Yeah, Joan, we can relate.

Rivers wasn't finished, getting in a dig at Bristol Palin and her foray into reality TV.
The situation begs the question: Did Sarah herself call this one in to her FOX bosses in order to punish Joan? The comic certainly hopes the presidential contender has better things to do than listen to her. "If Sarah is listening to what we say, we're in trouble," Joan says.
...
Joan has another reason for being upset, namely that this brouhaha has led her to regret voting for Sarah's daughter Bristol on 'Dancing With the Stars.'
"I actually voted for her terrible daughter over David Hasselhoff," she says. "I should've voted for David; they both sucked as dancers."
 I continued in the tip jar:
For another take on this controversy, watch the following video from CNN.
Joan Rivers: "I'm banned from Fox"
Here's a sneak peak at Joy's interview with the legendary Joan Rivers and her daughter Melissa. Joan says she was "uninvited" from Fox and Friends after ridiculing Sarah Palin. Do you think Joan is better off "banned?"
I say yes.  What say you?
People had a lot to say--197 comments after my tip jar.  WOW!  I won't reproduce any of them now; instead, click on the link to the Daily Kos diary and read them for yourselves.