ill take a stab,
1. you have added a E1 on the router that is connected directly to the PBX (the E1 is up and functional correct - you have multiframes established?)
2. What are the devices at the remote locations? - do you have another PBX there as well or some analog phones?
3. if the E1 is up and you dial, does it reach any of the E1 ports?
4. if you dont see anything on the ports (do a show voice call stat) then trace back from port to PBX.
5. Have you added route members etc on the PBX to tell it to grab the E1 trunk (Your side of course) and send it across if the user is trying to dial a remote location extension.
hopefully this might give you some pointers and maybe you can be a little more specific than "VOIP calls are not happenning" :)