The problem and the solution are both here for any other naïve macro coders... 

I'm using Firefox and discovered that pressing control page down moves among the tabs. I've tried to enter a voice macro to do that called "next tab". The command is recognized by Dragon,and the macro is as simple as can be: 

Sub Main
    SendDragonKeys "Ctrl+PgDn"

End Sub 

Of course that doesn't work, because the command needs curly brackets. This one works: 

Sub Main
    SendDragonKeys "{Ctrl+PgDn}"
End Sub
 

You can also use Ctrl+Tab.

For a complete list of Firefox keyboard shortcuts see here:

http://www.mozilla.org/support/firefox/keyboard

Mike 

DNS 12.5 Pro -- Win7 64 -- i7 3770 -- 8GB RAM -- 120G SSD -- Knowbrainer Hands-Free Headset -- Andrea USB Pod