Version:           2.6.2 (using KDE KDE 3.5.2)
Installed from:    Gentoo Packages
Compiler:          gcc-4.1.0 
OS:                Linux

Ark crashes when quitting, producing this backtrace:

Using host libthread_db library "/lib/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread 47337096087040 (LWP 10982)]
0x00002b0d86b213f0 in nanosleep () from /lib/libc.so.6
#0  0x00002b0d86b213f0 in nanosleep () from /lib/libc.so.6
#1  0x00002b0d86b21244 in sleep () from /lib/libc.so.6
#2  0x00002b0d83a468cb in KCrash::startDrKonqi ()
   from /usr/kde/3.5/lib64/libkdecore.so.4
#3  0x00002b0d83a46f00 in KCrash::defaultCrashHandler ()
   from /usr/kde/3.5/lib64/libkdecore.so.4
#4  0x00002b0d86ac3640 in killpg () from /lib/libc.so.6
#5  0x0000000000000000 in ?? ()

the crash seems independent of the archive used. I reproduced it on a gzipped file containing "some text" which I will attach below. I ran ark from konsole on said file and it produced the following output:

marijn@hakbak ~ $ ark crashark.gz
ark (kdeutils): ArkPart::ArkPart
kdecore (kdelibs): KTempDir: Temporary directory created :/tmp/kde-marijn/arkOMqCXl/
kdecore (KConfigSkeleton): Creating KConfigSkeleton (0x74ee30)
kdecore (KConfigSkeleton): KConfigSkeleton::readConfig()
ark (kdeutils): ArkWidget::createFileListView
kparts: MainWindow::createGUI, part=0x7272b0 ArkPart ArkPart
ark (kdeutils): File to open: /home/marijn/crashark.gz
kio (KMimeType): WARNING: mimetype not valid '' (missing entry in the file ?)
kio (KMimeType): WARNING: mimetype not valid '' (missing entry in the file ?)
kio (KSycoca): Trying to open ksycoca from /var/tmp/kdecache-marijn/ksycoca
ark (kdeutils): find by url: application/x-gzip
ark (kdeutils): m_openAsMimeType is:
ark (kdeutils): CompressedFile constructor
kdecore (kdelibs): KTempDir: Temporary directory created :/tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/
ark (kdeutils): +CompressedFile::open
kio (KIOJob): kio_uiserver registered
ark (kdeutils): Temp file name is /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/crashark.gz
ark (kdeutils): Command is gunzip /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/crashark.gz
ark (kdeutils): -CompressedFile::open
kparts: WARNING: StatusBarExtension::removeStatusBarItem. Widget not found : [KPushButton pointer (0x723bc0) to widget CancelButton, geometry=100x30+0+0]
marijn@hakbak ~ $ ark (kdeutils): normalExit = true
ark (kdeutils): exitStatus = 0
kio (KIOJob): stat file:///tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/crashark
ark (kdeutils):  Real name of file:///home/marijn/crashark.gz is /home/marijn/crashark.gz
ark (kdeutils): Saved ptr [MainWindow pointer (0x510590) to widget ark-mainwindow#1, geometry=1594x1127+0+0] added open ark: /home/marijn/crashark.gz
ark: [static bool KTempDir::removeDir(const QString&)]  /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/
ark: Checking directory for remove /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/
ark: File /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/ is DIRECTORY!
ark: CHECKING /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//.
ark: CHECKING /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//..
ark: CHECKING /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//crashark
ark: RECURSE: /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//crashark
ark: Checking directory for remove /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//crashark
ark: UNLINKING file /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//crashark
ark: CHECKING /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//.
ark: CHECKING /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6//..
ark: RMDIR dir /tmp/kde-marijn/arkOMqCXl/compressed_file_tempRA5IK6/
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = ark path = <unknown> pid = 10982