Adam,Is it not possible that the 3750e is on the wrong vlan connecting to the 6500? show ip eigrp neighborsEIGRP-IPv4 Neighbors for AS(500)H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq                                   ...

What type of switches are Switch A and B? Tony       Are you sure they have CDP?

I agree CDP is not required; however l2 adjacency must be available, CDP is a good way of seeing that Layer 2 is working. as it'll show up even if someone has made a mistake and allocated the wrong ip address.Can Switch B ping Router B? can switch B...

Steve,Excellent glad you got it working.First thing that strikes about the second problem is that it's different subnet. Why don't you just create a new vlan on the router. You can have 4 vlans on those routers. You can have them both going at once ...