Ah, forgot:

Fedora 9, updates-testing packages.

Confirming on KDE-4.1.0 with the backtrace below.

Steps to reproduce:

1) Open dolphin and enter svn+http://www.alwins-world.de/repos/kdesvn/trunk?rev=100 into the address bar


Backtrace:

Application: Dolphin (dolphin), signal SIGABRT
[Thread debugging using libthread_db enabled]
[New Thread 0xb60ba700 (LWP 19565)]
[KCrash handler]
#6  0xffffe424 in __kernel_vsyscall ()
#7  0xb63a9690 in *__GI_raise (sig=6)
    at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#8  0xb63aaed8 in *__GI_abort () at abort.c:88
#9  0xb742b097 in qt_message_output (msgType=QtFatalMsg, 
    buf=0xbf8950fc "ASSERT: \"result.second\" in file /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/kdirmodel.cpp, line 308")
    at global/qglobal.cpp:2058
#10 0xb742b14f in qFatal (msg=0xb757eab4 "ASSERT: \"%s\" in file %s, line %d")
    at global/qglobal.cpp:2260
#11 0xb742b5cb in qt_assert (assertion=0xb7e51828 "result.second", 
    file=0xb7e514a8 "/var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/kdirmodel.cpp", line=308) at global/qglobal.cpp:1828
#12 0xb7d41d0c in KDirModelPrivate::_k_slotNewItems (this=0x8455ed8, 
    items=@0x847e3c8)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/kdirmodel.cpp:308
#13 0xb7d4245c in KDirModel::qt_metacall (this=0x8455e58, 
    _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0xbf89733c)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/kdirmodel.moc:76
#14 0xb753e530 in QMetaObject::activate (sender=0x8455d78, 
    from_signal_index=<value optimized out>, to_signal_index=13, 
    argv=<value optimized out>) at kernel/qobject.cpp:3001
#15 0xb753ec92 in QMetaObject::activate (sender=0x8455d78, m=0x809f1f0, 
    local_signal_index=9, argv=0xbf89733c) at kernel/qobject.cpp:3071
#16 0xb7d2b90f in KDirLister::newItems (this=0x8455d78, _t1=@0x847e3c8)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/kdirlister.moc:253
#17 0xb7d2beac in KDirLister::Private::emitItems (this=0x8455d98)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/kdirlister.cpp:2202
#18 0xb7d308a4 in KDirListerCache::slotEntries (this=0x8178b20, 
    job=0x845ffb0, entries=@0xbf897814)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/kdirlister.cpp:977
#19 0xb7d36094 in KDirListerCache::qt_metacall (this=0x8178b20, 
    _c=QMetaObject::InvokeMetaMethod, _id=11, _a=0xbf897588)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/kdirlister_p.moc:97
#20 0xb753e530 in QMetaObject::activate (sender=0x845ffb0, 
    from_signal_index=<value optimized out>, to_signal_index=40, 
    argv=<value optimized out>) at kernel/qobject.cpp:3001
#21 0xb753ec92 in QMetaObject::activate (sender=0x845ffb0, m=0xb7e70560, 
    local_signal_index=0, argv=0xbf897588) at kernel/qobject.cpp:3071
#22 0xb7d0befd in KIO::ListJob::entries (this=0x845ffb0, _t1=0x845ffb0, 
    _t2=@0xbf897814)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/jobclasses.moc:763
#23 0xb7d14b0e in KIO::ListJobPrivate::slotListEntries (this=0x82d8468, 
    list=@0xbf897814)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/job.cpp:2318
#24 0xb7d14e00 in KIO::ListJob::qt_metacall (this=0x845ffb0, 
    _c=QMetaObject::InvokeMetaMethod, _id=6, _a=0xbf89771c)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/jobclasses.moc:750
#25 0xb753e530 in QMetaObject::activate (sender=0x82d8f68, 
    from_signal_index=<value optimized out>, to_signal_index=10, 
    argv=<value optimized out>) at kernel/qobject.cpp:3001
#26 0xb753ec92 in QMetaObject::activate (sender=0x82d8f68, m=0xb7e72f44, 
    local_signal_index=6, argv=0xbf89771c) at kernel/qobject.cpp:3071
#27 0xb7dae95f in KIO::SlaveInterface::listEntries (this=0x82d8f68, 
    _t1=@0xbf897814)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/slaveinterface.moc:175
#28 0xb7db059b in KIO::SlaveInterface::dispatch (this=0x82d8f68, _cmd=106, 
    rawdata=@0xbf897874)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/slaveinterface.cpp:195
#29 0xb7db0f9b in KIO::SlaveInterface::dispatch (this=0x82d8f68)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/slaveinterface.cpp:90
#30 0xb7da4115 in KIO::Slave::gotInput (this=0x82d8f68)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/slave.cpp:319
#31 0xb7da5585 in KIO::Slave::qt_metacall (this=0x82d8f68, 
    _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbf897978)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/slave.moc:75
#32 0xb753e530 in QMetaObject::activate (sender=0x8461f98, 
    from_signal_index=<value optimized out>, to_signal_index=4, 
    argv=<value optimized out>) at kernel/qobject.cpp:3001
#33 0xb753ec92 in QMetaObject::activate (sender=0x8461f98, m=0xb7e6fba0, 
    local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3071
#34 0xb7ce4b6d in KIO::Connection::readyRead (this=0x8461f98)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/connection.moc:84
#35 0xb7ce581d in KIO::ConnectionPrivate::dequeue (this=0x8406270)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kio/kio/connection.cpp:82
#36 0xb7ce6595 in KIO::Connection::qt_metacall (this=0x8461f98, 
    _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0x846a240)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs_build/kio/connection.moc:72
#37 0xb7538249 in QMetaCallEvent::placeMetaCall (this=0x840ced0, 
    object=0x8461f98) at kernel/qobject.cpp:535
#38 0xb753a309 in QObject::event (this=0x8461f98, e=0x840ced0)
    at kernel/qobject.cpp:1131
#39 0xb68398a4 in QApplicationPrivate::notify_helper (this=0x80affa0, 
    receiver=0x8461f98, e=0x840ced0) at kernel/qapplication.cpp:3772
#40 0xb683da75 in QApplication::notify (this=0xbf89812c, receiver=0x8461f98, 
    e=0x840ced0) at kernel/qapplication.cpp:3366
#41 0xb7afa6c3 in KApplication::notify (this=0xbf89812c, receiver=0x8461f98, 
    event=0x840ced0)
    at /var/tmp/portage/kde-base/kdelibs-4.1.0/work/kdelibs-4.1.0/kdeui/kernel/kapplication.cpp:311
#42 0xb7528d59 in QCoreApplication::notifyInternal (this=0xbf89812c, 
    receiver=0x8461f98, event=0x840ced0) at kernel/qcoreapplication.cpp:587
#43 0xb752a006 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, 
    event_type=0, data=0x80a0808) at kernel/qcoreapplication.h:215
#44 0xb752a35d in QCoreApplication::sendPostedEvents (receiver=0x0, 
    event_type=0) at kernel/qcoreapplication.cpp:1091
#45 0xb68c9d7e in QEventDispatcherX11::processEvents (this=0x80afcc8, 
    flags=@0xbf898048)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#46 0xb75280d3 in QEventLoop::processEvents (this=0xbf8980c0, 
    flags=@0xbf898088) at kernel/qeventloop.cpp:149
#47 0xb7528246 in QEventLoop::exec (this=0xbf8980c0, flags=@0xbf8980c8)
    at kernel/qeventloop.cpp:200
#48 0xb752a401 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:845
#49 0xb683923f in QApplication::exec () at kernel/qapplication.cpp:3304
#50 0x0807f238 in main (argc=6, argv=0xbf8982e4)
    at /var/tmp/portage/kde-base/dolphin-4.1.0/work/dolphin-4.1.0/apps/dolphin/src/main.cpp:94
#0  0xffffe424 in __kernel_vsyscall ()

I can't reproduce this (I get a "URL cannot be listed" error), but the backtrace looks just like the one I get for bug 160057, it's probably a duplicate.

Hm. 
I reproduced it with kubuntu 8.04 and kde4 packages there, too. 

And can not listed ... I tried url above again with kde3 (konqueror) - works perfekt, ?rev=xxx let change revision to browse so it should work. If it is a duplicate I can not say - but looks similar. 

I'd checked the subversion kio module again - it gives a correct listing. When it works without ?rev=xxx than with ?rev=HEAD it should work, too, cause it sends exact same content but crashes (or in your case lists nothing)

This was because of KDirModel being confused by the queries (child items didn't look like children of their parent URL). Fixed in KDirModel by removing queries and fragments before comparing urls to find a node by its URL.

Trunk r865989+865992, branch r865995.