Seems this is the right one. It happens to me as well on kde 3.5.7. This is my backtrace:
Using host libthread_db library "/lib/i686/cmov/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread -1243031856 (LWP 9057)]
[KCrash handler]
#6  0xb7cbba1c in memcpy () from /lib/i686/cmov/libc.so.6
#7  0xb5707153 in c4_String::Init (this=0xb562cc6c, p=0x80aa39b, n=135651325)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/mk4storage/metakit/src/string.cpp:212
#8  0xb571bb03 in c4_HandlerSeq::Prepare (this=0x80a9bb8, ptr_=0xbf8acc60, 
    selfDesc_=true)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/mk4storage/metakit/src/../include/mk4str.inl:209
#9  0xb571fea5 in c4_Persist::LoadAll (this=0x80aa2e8)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/mk4storage/metakit/src/persist.cpp:1043
#10 0xb572010d in c4_Storage (this=0x80abf60, 
    fname_=0x80aa138 "/home/rasasi/.kde/share/apps/akregator/Archive/archiveindex.mk4", mode_=1)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/mk4storage/metakit/src/store.cpp:217
#11 0xb5702971 in Akregator::Backend::StorageMK4Impl::open (this=0x80a9da0, 
    autoCommit=true)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/mk4storage/storagemk4impl.cpp:129
#12 0xb5a17aab in Part (this=0x8116528, parentWidget=0x8098500, 
    parent=0x8098500, name=0x8052f3d "akregator_part")
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/akregator_part.cpp:181
#13 0xb5a25808 in KParts::GenericFactory<Akregator::Part>::createPartObject (
    this=0x81102a8, parentWidget=0x8098500, 
    widgetName=0x8052f3d "akregator_part", parent=0x8098500, 
    name=0x8052f3d "akregator_part", 
    className=0x8052f28 "KParts::ReadOnlyPart", args=@0xbf8acf00)
    at /usr/include/kde/kgenericfactory.tcc:146
#14 0xb7f6177f in KParts::Factory::createPart (this=0x81102a8, 
    parentWidget=0x8098500, widgetName=0x8052f3d "akregator_part", 
    parent=0x8098500, name=0x8052f3d "akregator_part", 
    classname=0x8052f28 "KParts::ReadOnlyPart", args=@0xbf8acf00)
    at /tmp/buildd/kdelibs-3.5.7.dfsg.1/./kparts/factory.cpp:44
#15 0xb7f617e1 in KParts::Factory::createObject (this=0x81102a8, 
    parent=0x8098500, name=0x8052f3d "akregator_part", 
    classname=0x8052f28 "KParts::ReadOnlyPart", args=@0xbf8acf00)
    at /tmp/buildd/kdelibs-3.5.7.dfsg.1/./kparts/factory.cpp:80
#16 0xb76a3931 in KLibFactory::create (this=0x81102a8, parent=0x8098500, 
    name=0x8052f3d "akregator_part", 
    classname=0x8052f28 "KParts::ReadOnlyPart", args=@0xbf8acf00)
    at /tmp/buildd/kdelibs-3.5.7.dfsg.1/./kdecore/klibloader.cpp:83
#17 0x08051dc7 in Akregator::MainWindow::loadPart (this=0x8098500)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/mainwindow.cpp:107
#18 0x080524e9 in Akregator::Application::newInstance (this=0xbf8ad690)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/main.cpp:61
#19 0xb7769b86 in KUniqueApplication::newInstanceNoFork (this=0xbf8ad690)
    at /tmp/buildd/kdelibs-3.5.7.dfsg.1/./kdecore/kuniqueapplication.cpp:378
#20 0xb776ff28 in KUniqueApplication::qt_invoke (this=0xbf8ad690, _id=20, 
    _o=0xbf8ad098) at ./kuniqueapplication.moc:87
#21 0xb70a9e1b in QObject::activate_signal (this=0x809dff8, clist=0x8095650, 
    o=0xbf8ad098) at kernel/qobject.cpp:2356
#22 0xb7432f87 in QSignal::signal (this=0x809dff8, t0=@0x809e020)
    at .moc/debug-shared-mt/moc_qsignal.cpp:100
#23 0xb70c999e in QSignal::activate (this=0x809dff8) at kernel/qsignal.cpp:212
#24 0xb70d1370 in QSingleShotTimer::event (this=0x809dfd0)
    at kernel/qtimer.cpp:286
#25 0xb7041cf2 in QApplication::internalNotify (this=0xbf8ad690, 
    receiver=0x809dfd0, e=0xbf8ad408) at kernel/qapplication.cpp:2635
#26 0xb7043b0f in QApplication::notify (this=0xbf8ad690, receiver=0x809dfd0, 
    e=0xbf8ad408) at kernel/qapplication.cpp:2358
#27 0xb775b142 in KApplication::notify (this=0xbf8ad690, receiver=0x809dfd0, 
    event=0xbf8ad408)
    at /tmp/buildd/kdelibs-3.5.7.dfsg.1/./kdecore/kapplication.cpp:550
#28 0xb6fd54c1 in QApplication::sendEvent (receiver=0x809dfd0, 
    event=0xbf8ad408) at ../include/qapplication.h:520
#29 0xb70346c3 in QEventLoop::activateTimers (this=0x806e5e0)
    at kernel/qeventloop_unix.cpp:556
#30 0xb6fe980f in QEventLoop::processEvents (this=0x806e5e0, flags=4)
    at kernel/qeventloop_x11.cpp:389
#31 0xb705c245 in QEventLoop::enterLoop (this=0x806e5e0)
    at kernel/qeventloop.cpp:198
#32 0xb705c066 in QEventLoop::exec (this=0x806e5e0)
    at kernel/qeventloop.cpp:145
#33 0xb704388b in QApplication::exec (this=0xbf8ad690)
    at kernel/qapplication.cpp:2758
#34 0x0805174e in main (argc=)
    at /tmp/buildd/kdepim-3.5.7/./akregator/src/main.cpp:112
#35 0xb7c61ebc in __libc_start_main () from /lib/i686/cmov/libc.so.6
#36 0x08050a21 in _start ()

And also I'll attach a tarball for the ~/.kde/share/apps/akregator dir which makes possible to reproduce the problem. A little later I'll try to isolate the blaming corrupted file.