nepomukservicestub crashed with SIGSEGV in QCoreApplication::notifyInternal()

I have no idea how to do, it's only happen when my computer is starting

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: kde-runtime 4:4.8.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-18.28-generic-pae 3.2.9
Uname: Linux 3.2.0-18-generic-pae i686
ApportVersion: 1.94-0ubuntu1
Architecture: i386
Date: Tue Mar 6 12:06:16 2012
Disassembly: => 0x0: Cannot access memory at address 0x0
ExecutablePath: /usr/bin/nepomukservicestub
ProcCmdline: /usr/bin/nepomukservicestub nepomukfileindexer
ProcEnviron:
 LANGUAGE=es_CO:es
 LANG=es_CO.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x0: Cannot access memory at address 0x0
 PC (0x00000000) not located in a known VMA region (needed executable region)!
 Stack memory exhausted (SP below stack segment)
SegvReason: executing NULL VMA
Signal: 11
SourcePackage: kde-runtime
StacktraceTop:
 ?? ()
 QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
 ?? () from /usr/lib/i386-linux-gnu/libQtCore.so.4
 g_main_context_dispatch () from /lib/i386-linux-gnu/libglib-2.0.so.0
 ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
Title: nepomukservicestub crashed with SIGSEGV in QCoreApplication::notifyInternal()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo