Vista / Win 7 box can access and copy share but not execute

Hi all,

Trying to get a Vista / Win 7 laptop to access a share (e$) on another
laptop running XP Pro, so I can run various application installers stored
there. Other XP laptops have no problems mapping a drive and executing the
setup.exe stored there.

Whenever I try this on a Vista / Win 7 laptop, the laptop will map the
share. It *will* let me copy the files and folders over. But it *won't* let
me execute any exe stored on the mapped share. Is this UAC or some new
security setting unique to Vista / Win 7?

Again, no problem doing this on an XP box. It just seems odd that Vista/Win
7 will allow me to copy an installer folder to the local desktop, but it
won't let me run a program stored on the same share.

Ideas?

Thanks,
Sir_timbit