Thank you. I’d be happy for an explanation of what “my money is in your possession” means. In this case, the recipient of the money traveled overseas {Tosafot}. The money is not with the one who hired them.

It doesn’t matter. The money exists in the world and is not with the witnesses. “My money is in your possession” means a claim rooted in the demand to give me my money that is with you, as opposed to a claim for compensation (as in damages).

So why does the Talmud speak about one who hires false witnesses for his fellow, and not about one who gives false testimony for his fellow? I understood it to mean that the witnesses also traveled overseas, but if they were here they would be liable under human law (and they would then claim the money back from the person who received the money based on their testimony).

Because the discussion there is about cases of indirect causation in damages.

Maybe I didn’t understand what the Rabbi answered. The questioner asked why the witnesses are exempt, and the Rabbi answered that they are exempt because this is a claim of “my money is in your possession.” But even according to that, the witnesses should still be liable under the law of Heaven. After all, it can’t be that their punishment is less severe than that of the person who only hired them. So according to that, the Talmud should have brought the case of one who gives false testimony for his fellow, which is a simpler case. Unless in such a case the witnesses are liable under human law, and that’s why the Talmud doesn’t bring it. So the answer to the questioner, as I understand it, is that the witnesses are liable under human law, but they are not present, and therefore the liability shifts to the one who hired them—but only under the law of Heaven, because he merely caused it indirectly.

This really does require analysis, because although the one who hired them caused the damage that they did, the witnesses too caused damage only indirectly (since they did not take the money from him with their own hands). Perhaps the Talmud wanted to make the novel point that even the one who hired them is liable under the law of Heaven, and not only the witnesses, even though his is a more remote form of indirect causation.
Furthermore, one has to consider how it was discovered that they lied. If they were proven to be conspiring witnesses, then they are liable to pay under the rule of “as he plotted to do” (although here it was actually carried out; in monetary cases, perhaps conspiring witnesses are punished even when they actually carried it out), and so with respect to them perhaps it is obvious.
But this still requires further study.

Thank you very much to you too, Yonatan, for sharpening the point.