Slowly Fading Movie Clips In And Out

I’ve been messing with some code from the Kirupa site - I’m trying to attach a number of movie clips and then apply a slow fade in and out effect rather than a fast animation. The other requirement is that the animation should be continuous. Has anyone seen any _alpha fader code that can be used this way? I’m attaching an MX 2004 file that will give you an idea of what I’m looking for (except I need to slow the animation way down and get rid of any _x and _y scaling). For some reason, when I tweak the numbers to slow things down in this particular code I get a lot of artifacts in the Flash player - looks terrible. I’m sure there’s a simpler way to do this too. Thanks for any help/recommendations.