Random stopping

When I play file locally, as in preview it through Fl CS4 it views fine all the buttons work and everything transitions smoothly. However, when I view it in Firefox or Google Chrome I get bizarre stops that occur as a fade transition is happening. When I the file in IE, everything appears to to transition smoothly.

the file can be found at www.ericschuppe.com/website.html

-Where the problem occurs when you transition between buttons(I.E clicking About then Portfolio then Contact usually the fade doesn’t finish tweening), usually will only happen the first time you click
-I’ve tried different computers, versions of browsers…all same issue
-Re-exporting doesn’t work
-I’ve tried editing the actionscript that controls the fade when the button is clicked
I can post sections of code if you need that

Thanks ahead of time,