paypal button doesn't work on Safari. but works on Firefox

I have over 100 pairs of "Add to Cart" buttons on my website. One of each is on the individual item page and the other is on my Order Form.

I have one button that works on the order form, but the identical button doesn't work on the individual page when using SAFARI, but works when I use FIREFOX!

I have recreated the button several times and put it in the proper place several times, saved the changes and republished. Still it doesn't work in Safari!

This must be a Safari issue not a PayPal issue

Any suggestions?