approve or approve of

1. I'm Paris Hilton and I approve this message cause I think it's like totally hot.
2. I'm Paris Hilton and I approve OF this message cause I think it's like totally hot.

Which one is more correct?

#1 is correct.

To approve OF something is to agree with it, but in a passive sense. You are neither the author of it, nor do you have any personal responsibility at stake.

To approve something (no of) is to actively endorse it and let it go forward as an official act -- such as when a bank approves a loan, a politician approves a political campaign message, or a committee approves a budget.

They are different usages.

Thus, 2 is also correct, but has a different meaning to 1.

But int he context of Paris Hilton's spoof campaign, the correct answer is #1. I think the poster was just trying to figure out why she wasn't using #2.