Starting 2 slaves on the ssme box.
${MONGOHOME}/bin/mongod --dbpath /mnt/data/leadpoint --slave --source ip-10-166-57-74:10000 --port 10002 --fork --logpath /mnt/data/logs/db1 --maxConns 5000 --oplogSize 50000 --autoresync
${MONGOHOME}/bin/mongod --dbpath /mnt/data/leadpoint2 --slave --source ip-10-166-57-74:10000 --port 10001 --fork --logpath /mnt/data/logs/db2 --maxConns 5000 --oplogSize 50000 --autoresync

Have problem starting one of the slaves.
[root@ip-10-160-26-159 ~]# !ps
ps auxww | grep mongo
root 17220 50.6 27.3 5492692 2156660 ? Sl 11:18 3:09 /root/mongodb-linux-x86_64-1.6.4/bin/mongod --dbpath /mnt/data/leadpoint2 --slave --source ip-10-166-57-74:10000 --port 10001 --fork --logpath /mnt/data/logs/db2 --maxConns 5000 --oplogSize 50000 --autoresync
root 17285 0.0 0.0 6024 608 pts/0 S+ 11:24 0:00 grep mongo

[root@ip-10-160-26-159 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 10403128 5724644 4154196 58% /
/dev/sdb 433455904 188227504 223210096 46% /mnt
none 3936020 0 3936020 0% /dev/shm

Tue Nov 23 11:18:40 MongoDB starting : pid=17214 port=10000 dbpath=/mnt/data/leadpoint slave=1 64-bit
Tue Nov 23 11:18:40 db version v1.6.4, pdfile version 4.5
Tue Nov 23 11:18:40 git version: 4f5c02f8d92ff213b71b88f5eb643b7f62b50abc
Tue Nov 23 11:18:40 sys info: Linux domU-12-31-39-06-79-A1 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41
Tue Nov 23 11:18:40 [initandlisten] local.system.namespaces Assertion failure magic == 0x41424344 db/pdfile.h 241
0x534a61 0x54163f 0x7216f3 0x721d96 0x74ad8f 0x6133b8 0x73c14a 0x741cb0 0x746602 0x74715f 0x747ba7 0x5ff81a 0x70518a 0x7087c6 0x7092b1 0x56d9a8 0x557f1a 0x6ff306 0x822b65 0x8259bc
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo12sayDbContextEPKc+0xb1) [0x534a61]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo8assertedEPKcS1_j+0x10f) [0x54163f]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo11DataFileMgr7findAllEPKcRKNS_7DiskLocE+0x143) [0x7216f3]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo13findTableScanEPKcRKNS_7BSONObjERKNS_7DiskLocE+0xe6) [0x721d96]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZNK5mongo9QueryPlan9newCursorERKNS_7DiskLocEi+0x8ef) [0x74ad8f]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo11UserQueryOp5_initEv+0x3a8) [0x6133b8]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo12QueryPlanSet6Runner6initOpERNS_7QueryOpE+0x11a) [0x73c14a]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo12QueryPlanSet6Runner3runEv+0x290) [0x741cb0]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo12QueryPlanSet5runOpERNS_7QueryOpE+0x232) [0x746602]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo16MultiPlanScanner9runOpOnceERNS_7QueryOpE+0x5f) [0x74715f]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo16MultiPlanScanner5runOpERNS_7QueryOpE+0x17) [0x747ba7]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(ZN5mongo8runQueryERNS_7MessageERNS_12QueryMessageERNS_5CurOpES1+0x103a) [0x5ff81a]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod [0x70518a]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_8SockAddrE+0x14d6) [0x7087c6]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo14DBDirectClient4callERNS_7MessageES2_b+0x81) [0x7092b1]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo14DBClientCursor4initEv+0x148) [0x56d9a8]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo12DBClientBase5queryERKSsNS_5QueryEiiPKNS_7BSONObjEii+0x32a) [0x557f1a]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo14DBDirectClient5queryERKSsNS_5QueryEiiPKNS_7BSONObjEi+0x56) [0x6ff306]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo19clearTmpCollectionsEv+0x185) [0x822b65]
/root/mongodb-linux-x86_64-1.6.4/bin/mongod(_ZN5mongo14_initAndListenEiPKc+0x41c) [0x8259bc]
Tue Nov 23 11:18:40 [initandlisten] assertion 0 assertion db/pdfile.h:241 ns:local.system.namespaces query:

{ name: /^local.temp./ }

Tue Nov 23 11:18:40 [initandlisten] Dropping old temporary collection:
Tue Nov 23 11:18:40 [initandlisten] exception in initAndListen std::exception: no collection name, terminating
Tue Nov 23 11:18:40 dbexit:

Tue Nov 23 11:18:40 [initandlisten] shutdown: going to close listening sockets...
Tue Nov 23 11:18:40 [initandlisten] shutdown: going to flush oplog...
Tue Nov 23 11:18:40 [initandlisten] shutdown: going to close sockets...
Tue Nov 23 11:18:40 [initandlisten] shutdown: waiting for fs preallocator...
Tue Nov 23 11:18:40 [initandlisten] shutdown: closing all files...
Tue Nov 23 11:18:40 closeAllFiles() finished

Tue Nov 23 11:18:40 [initandlisten] shutdown: removing fs lock...
Tue Nov 23 11:18:40 dbexit: really exiting now