Geturl issue

Hello all,
I have an interesting situation here,
using V10 Flash, I programed a simple get url button on a MC that I set as a button in priorities menu.
on the main time line I put my script get url, self target . . nothing unusual.

here is the issue, I am not getting the same response from the button on several computers.
some computers require a second click in order to get into the site.
I tried the 'button on 2 macs and 2 pc’s here in my home and the button works fine, other people say they either can’t get in or they have to click on the link twice . . .
any ideas?
thanks in advance
gp