Ok, there are a few very simple mistakes here, let me walk you through them.

The first is not really a mistake, but is definetly something you should know to make better Flash animations; try to do as much as you can in Flash!

The second layer contains images which you want to animate over the first. This is fair enough, but the animation you are doing is very simple and there is no need to have individual frames, each with their own 'shiny bit'! There are quite a few images there and therefore you end .swf movie is 168kb for an animation that lasts only a few seconds and, if you blink, you miss it! There is a much better way to do this...

Get the 'shiny bit' that you created and using a good graphics program (Photoshop can definetly do this) save it as a transparent PNG (ask me if you're not sure about this). You can then import this 'shiny bit' into Flash (Flash will preserve it's transparency) and then use Flash to animate this small image moving over your logo, fading in and out. This will look practically identical and give you a file half the size.

Secondly, I'm not really sure why you have a motion tween on the bottom layer. That symbol does not change at all - it does nothing. So there is no need for a motion tween. You'll also notice that (if you click on these frames and then the image) the image on this layer in the first frame is symbol 31 (you can see this in the properties panel), but the image on the last frame is symbol 21. If you want to actually do a motion tween then the symbol before the tween must be the same as the symbol after the tween.

Thirdly, if you simply 'lock' the middle layer (click the small black circle under the padlock on this layer) you'll find you can now directly click on the bottom layer's symbol. It's likely that before you were clicking on the image to access it's actions, but you were seeing the 'actions' entry on the menu greyed out because you were, in fact, selecting the image on the layer above instead! This is definetly something you need to be careful of. Always lock or hide (the eye icon) any layers which you aren't using, if they are in the way of other layers you're currently editing. This takes a little getting used to, but it means that you don't acidentally edit the actions/properties/whatever, of the wrong symbol.

In terms of adding the actions now, you're going to need to have the user click on the movieclip of the image with the 'shiny thing'. I, personally, don't think this would be very easy, as you would need to add this to a movieclip... which can be done but means that the user doesn't see a 'hand' (indicating that there is a link) when they move over a movieclip, even if it is linking. So then you would have to put a button inside the movieclip... and this is when things get unneccessarily complicated.

There's an easier way: On your main timeline (the original timeline with these 3 layers), just make a new layer, above your image with the 'shiny bit' and, wherever you want the button to be, make a large square. Select the square, and convert it into a button. The in the properties panel, under 'Color', choose alpha and set this to 0%. The button will now be invisible, but still work perfectly. You can now add the actions you want to this button...

Ok, quite a lengthy post! Let us know how you get on or if you have any problems!