Change that toL
10.0.1.100 ip-10-0-1-100
10.0.2.100 ip-10-0-2-100
10.0.3.100 ip-10-0-3-100
Machines can find the IP addresses, they have problems mapping host names to IP addresses at times however.
This might not work either as I believe you stated that originally when you ran the rs.initiate(...) from the mongo shell originally.