In "X-Men Origins: Wolverine", Silverfox tried to use her seduction powers over Sabertooth while he was chocking her, but they didn't work. Why is this?

My guess would be that she was unable to seduce him because he is a stronger mutant than she is. Or maybe because he was lifting her far off the ground and choking her making it extremely hard for her to concentrate her powers on him.

Once again, a question that was posted a long time ago, but I'm going to answer it anyway (again).

I believe her powers with being able to persuade anyone with touch show some sort of mental powers which could in some ways be called a form of telepathy, though a very limited one (not at all on the same level as someone like Charles Xavier or Jean Grey). In that case, there are some mutants who have trained themselves to have defensive shields against telepaths (though some have it naturally) so he could have either defense.

It is also worth noting that both Victor and Logan have healing factor, so it's possible that something like that attributes to helping block mental attacks, though it's unlikely.

It's also possible that since she was clearly under stress from trying to keep her sister alive and get her out without Stryker hurting her and then surprised when Sabretooth tried to kill her, that she either or both didn't have the strength or wasn't prepared to use her powers.

I was thinking he was stronger than her.
Her powers don't work on Wolverine either.