> db.foo.ensureIndex({a:"text"})
{
	"err" : "text search not enabled",
	"code" : 16633,
	"n" : 0,
	"connectionId" : 1,
	"ok" : 1
}

$ cat log
Tue Feb 26 21:27:07.680 [initandlisten] MongoDB starting : pid=11011 port=27017 dbpath=/data/db/ 64-bit host=Rassi-MacBook-Pro.local
Tue Feb 26 21:27:07.680 [initandlisten] 
Tue Feb 26 21:27:07.680 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000
Tue Feb 26 21:27:07.680 [initandlisten] db version v2.4.0-rc1-pre-, pdfile version 4.5
Tue Feb 26 21:27:07.680 [initandlisten] git version: bb3ecd589f2c7aa54d47a790400d095a5856ccba
Tue Feb 26 21:27:07.680 [initandlisten] build info: Darwin Rassi-MacBook-Pro.local 12.0.0 Darwin Kernel Version 12.0.0: Sun Jun 24 23:00:16 PDT 2012; root:xnu-2050.7.9~1/RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49
Tue Feb 26 21:27:07.680 [initandlisten] allocator: tcmalloc
Tue Feb 26 21:27:07.680 [initandlisten] options: { logpath: "log" }
Tue Feb 26 21:27:07.683 [initandlisten] journal dir=/data/db/journal
Tue Feb 26 21:27:07.683 [initandlisten] recover : no journal files present, no recovery needed
Tue Feb 26 21:27:07.721 [websvr] admin web console waiting for connections on port 28017
Tue Feb 26 21:27:07.721 [initandlisten] waiting for connections on port 27017
Tue Feb 26 21:27:14.199 [initandlisten] connection accepted from 127.0.0.1:58738 #1 (1 connection now open)
Tue Feb 26 21:27:14.215 [conn1] Assertion: 16633:text search not enabled
0x10d212d6b 0x10d1ec97e 0x10cf5d630 0x10cfa5f32 0x10d038245 0x10d039162 0x10cfb9e61 0x10cfba77a 0x10cfbfe15 0x10cde5922 0x10d208809 0x10d2456a5 0x7fff82254782 0x7fff822411c1 
 0   mongod                              0x000000010d212d6b _ZN5mongo15printStackTraceERSo + 43
 1   mongod                              0x000000010d1ec97e _ZN5mongo11msgassertedEiPKc + 174
 2   mongod                              0x000000010cf5d630 _ZN5mongo3fts14FTSIndexPlugin13postBuildHookERKNS_9IndexSpecE + 0
 3   mongod                              0x000000010cfa5f32 _ZN5mongo19prepareToBuildIndexERKNS_7BSONObjEbbRSsRPNS_16NamespaceDetailsERS0_ + 3858
 4   mongod                              0x000000010d038245 _ZN5mongo11DataFileMgr6insertEPKcPKvibbbPb + 931
 5   mongod                              0x000000010d039162 _ZN5mongo11DataFileMgr16insertWithObjModEPKcRNS_7BSONObjEbb + 64
 6   mongod                              0x000000010cfb9e61 _ZN5mongo14checkAndInsertEPKcRNS_7BSONObjE + 241
 7   mongod                              0x000000010cfba77a _ZN5mongo14receivedInsertERNS_7MessageERNS_5CurOpE + 1882
 8   mongod                              0x000000010cfbfe15 _ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_11HostAndPortE + 6389
 9   mongod                              0x000000010cde5922 _ZN5mongo16MyMessageHandler7processERNS_7MessageEPNS_21AbstractMessagingPortEPNS_9LastErrorE + 198
 10  mongod                              0x000000010d208809 _ZN5mongo17PortMessageServer17handleIncomingMsgEPv + 1657
 11  mongod                              0x000000010d2456a5 thread_proxy + 229
 12  libsystem_c.dylib                   0x00007fff82254782 _pthread_start + 327
 13  libsystem_c.dylib                   0x00007fff822411c1 thread_start + 13
Tue Feb 26 21:27:14.218 [conn1] insert test.system.indexes keyUpdates:0 exception: text search not enabled code:16633 locks(micros) w:18694 3ms

> db.adminCommand({"getLog":"global"})
{
	"totalLinesWritten" : 15,
	"log" : [
		"Tue Feb 26 21:24:49.216 [initandlisten] MongoDB starting : pid=11009 port=27017 dbpath=/data/db/ 64-bit host=Rassi-MacBook-Pro.local",
		"Tue Feb 26 21:24:49.216 [initandlisten] ",
		"Tue Feb 26 21:24:49.216 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000",
		"Tue Feb 26 21:24:49.216 [initandlisten] db version v2.4.0-rc1-pre-, pdfile version 4.5",
		"Tue Feb 26 21:24:49.216 [initandlisten] git version: bb3ecd589f2c7aa54d47a790400d095a5856ccba",
		"Tue Feb 26 21:24:49.216 [initandlisten] build info: Darwin Rassi-MacBook-Pro.local 12.0.0 Darwin Kernel Version 12.0.0: Sun Jun 24 23:00:16 PDT 2012; root:xnu-2050.7.9~1/RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49",
		"Tue Feb 26 21:24:49.216 [initandlisten] allocator: tcmalloc",
		"Tue Feb 26 21:24:49.216 [initandlisten] options: {}",
		"Tue Feb 26 21:24:49.218 [initandlisten] journal dir=/data/db/journal",
		"Tue Feb 26 21:24:49.219 [initandlisten] recover : no journal files present, no recovery needed",
		"Tue Feb 26 21:24:49.260 [websvr] admin web console waiting for connections on port 28017",
		"Tue Feb 26 21:24:49.260 [initandlisten] waiting for connections on port 27017",
		"Tue Feb 26 21:25:21.361 [initandlisten] connection accepted from 127.0.0.1:58733 #1 (1 connection now open)",
		"Tue Feb 26 21:25:25.704 [conn1] Assertion: 16633:text search not enabled",
		"Tue Feb 26 21:25:25.708 [conn1] insert test.system.indexes keyUpdates:0 exception: text search not enabled code:16633 locks(micros) w:19226 4ms"
	],
	"ok" : 1
}
>