With clean db paths, started up:

$ ./mongod --dbpath ~/dbs/blort1 --replSet blort/ubuntu:27017
$ ./mongod --dbpath ~/dbs/blort2 --port 27018 --replSet blort/ubuntu:27017

Then opened the shell and ran:

> db.runCommand({replSetInitiate:{ "_id" : "blort", members : [{_id : 0, host:"ubuntu:27017"},{_id:1, host:"ubuntu:27018"}]}})
{
"info" : "Config now saved locally. Should come online in about a minute.",
"ok" : 1
}

ubuntu:27017 log:

[initandlisten] Wed Jul 14 11:01:24 connection accepted from 127.0.0.1:50457 #3
[conn3] Wed Jul 14 11:01:24 replSet replSetInitiate admin command received from client
[conn3] Wed Jul 14 11:01:24 replSet replSetInitiate config object parses ok, 2 members specified
[initandlisten] Wed Jul 14 11:01:24 connection accepted from 127.0.1.1:35364 #4
TEMP hb res cfg change:

TEMP hb res cfg change:

[conn3] Wed Jul 14 11:01:24 replSet replSetInitiate all members seem up
[conn3] Wed Jul 14 11:01:24 replSet info saving a newer config version to local.system.replset
[conn3] Wed Jul 14 11:01:24 replSet replSetInitiate config now saved locally. Should come online in about a minute.
[startReplSets] Wed Jul 14 11:01:30 Assertion failure lockedByMe() db/repl/rs.cpp 210
0x813a203 0x8143e55 0x8229368 0x822a00b 0x822a5cf 0x822c291 0x822d0eb 0x812faff 0xb47c1d 0xee380e 0x40aa0e
./mongod(_ZN5mongo12sayDbContextEPKc+0xc3) [0x813a203]
./mongod(_ZN5mongo8assertedEPKcS1_j+0xd5) [0x8143e55]
./mongod(_ZN5mongo11ReplSetImpl14initFromConfigERNS_13ReplSetConfigE+0x318) [0x8229368]
./mongod(_ZN5mongo11ReplSetImpl17_loadConfigFinishERSt6vectorINS_13ReplSetConfigESaIS2_EE+0x8b) [0x822a00b]
./mongod(_ZN5mongo11ReplSetImpl10loadConfigEv+0x42f) [0x822a5cf]
./mongod(_ZN5mongo11ReplSetImplC2ESs+0x781) [0x822c291]
./mongod(_ZN5mongo13startReplSetsEv+0x19b) [0x822d0eb]
./mongod(_ZN5boost6detail11thread_dataIPFvvEE3runEv+0xf) [0x812faff]
/usr/lib/libboost_thread-mt.so.1.38.0(thread_proxy+0x5d) [0xb47c1d]
/lib/tls/i686/cmov/libpthread.so.0 [0xee380e]
/lib/tls/i686/cmov/libc.so.6(clone+0x5e) [0x40aa0e]
[startReplSets] Wed Jul 14 11:01:30 replSet error loading configurations 0 assertion db/repl/rs.cpp:210
[startReplSets] Wed Jul 14 11:01:30 replSet error replication will not start
[startReplSets] Wed Jul 14 11:01:30 replSet error fatal error, stopping replication
[startReplSets] Wed Jul 14 11:01:30 replSet caught exception in startReplSets thread: assertion db/repl/rs.cpp:210
[conn1] Wed Jul 14 11:02:11 end connection 127.0.1.1:35359

ubuntu:27018 log:

[startReplSets] Wed Jul 14 11:01:12 replSet have you ran replSetInitiate yet?
[startReplSets] Wed Jul 14 11:01:12 replSet sleeping 20sec and will try again.
[initandlisten] Wed Jul 14 11:01:24 connection accepted from 127.0.1.1:59149 #2
[startReplSets] Wed Jul 14 11:01:32 Assertion failure lockedByMe() db/repl/rs.cpp 210
0x813a203 0x8143e55 0x8229368 0x822a00b 0x822a5cf 0x822c291 0x822d0eb 0x812faff 0x119c1d 0xe0180e 0x27da0e
./mongod(_ZN5mongo12sayDbContextEPKc+0xc3) [0x813a203]
./mongod(_ZN5mongo8assertedEPKcS1_j+0xd5) [0x8143e55]
./mongod(_ZN5mongo11ReplSetImpl14initFromConfigERNS_13ReplSetConfigE+0x318) [0x8229368]
./mongod(_ZN5mongo11ReplSetImpl17_loadConfigFinishERSt6vectorINS_13ReplSetConfigESaIS2_EE+0x8b) [0x822a00b]
./mongod(_ZN5mongo11ReplSetImpl10loadConfigEv+0x42f) [0x822a5cf]
./mongod(_ZN5mongo11ReplSetImplC2ESs+0x781) [0x822c291]
./mongod(_ZN5mongo13startReplSetsEv+0x19b) [0x822d0eb]
./mongod(_ZN5boost6detail11thread_dataIPFvvEE3runEv+0xf) [0x812faff]
/usr/lib/libboost_thread-mt.so.1.38.0(thread_proxy+0x5d) [0x119c1d]
/lib/tls/i686/cmov/libpthread.so.0 [0xe0180e]
/lib/tls/i686/cmov/libc.so.6(clone+0x5e) [0x27da0e]
[startReplSets] Wed Jul 14 11:01:32 replSet error loading configurations 0 assertion db/repl/rs.cpp:210
[startReplSets] Wed Jul 14 11:01:32 replSet error replication will not start
[startReplSets] Wed Jul 14 11:01:32 replSet error fatal error, stopping replication
[startReplSets] Wed Jul 14 11:01:32 replSet caught exception in startReplSets thread: assertion db/repl/rs.cpp:210