In/Out traffic not showing on each interface

I have a 2611 router with 4 interfaces (2 serial T1s and 2 Ethernet). In the Dashboard view the two Ethernet interfaces show activity on the IN Traffic column, but the OUT Traffic column shows no activity. On the Serial interfaces the results are similar except they are reversed, with the OUT Traffic column showing activity and the IN Traffic showing none. I was told by a friend that it could have to do with an ACL on the interface restricting flow information. If this is true I would like to know what I need to do to the ACL to fix it.

Something else is that is interesting is that the Quick View for three of the interfaces displays an appropriate graph showing no data for the direction that is reporting no activity in the Dashboard View. However, the Quick View for one of the Ethernet ports shows IN and OUT Traffic, even though it doesn't on the Dashboard. Not sure if this is relevant, but this is the interface that is configured as the flow-export source on the router.

Does anyone have a suggestion on how I can fix these two issues?

Thanks.