heh, i had a fair bit of a play with that .fla file, just a couple of notes before we get onto your question:
i suggest having a stop action before a new label or better yet on the start of a label, especially at the start of your movie
as atm it plays through to the news section by itself. (but the news mc doesnt play)…
also create layers for actions, this makes it lots easier to follow the frame level actions in your movies
a good layer name is “Actions”
hehe
now, onto your menu… As is i was having extreme problems trying to get it to work, probably just my n00biness, so i recommend that you make the menu this way:
Make “News” text, Convert to MC symbol (call newsMC) click newsMC and convert to button (call newsBut) double click newsBut and create blank keyframes on the over state (and hit to make it a nice square) then click the state where the MC currently resides, cut it, paste it into the Overstate…
Now double click this MC and get the text thats inside, copy it, and paste it into the currently 2 blank button states (up one level in newsBut) (1st state and 3rd state)…
Now back into newsMC - you put all your tweens inside this MC, with each button inside it on its own layer… assign the “gotoAndPlay” like you had onto the relevant button inside the MC and HOPEFULLY! it will work… 
im sorry its such a long way around it, but i did give your .fla a go and even with ALMOST getting it to a similiar state as the one i described, it might be better for you to do it this way before you go on to all your other buttons cringe…
Sorry again
hope it helps
YoSHi
p.s. check out www.cbtcafe.com in their flash mx tutorials / menus and buttons tutorials for their animated menus, it shows you a really good way to set out your overstate MC so its neat and easy to change, im sure kirupa has a similiar one, but thats the one i learnt from earlier this year so heh…