X11 libraries corrupted by VirtualBox crash

Question

I have a computer running Debian "Squeeze" 6.0-AMD64 which experienced a VirtualBox crash during a folder copy via SCP yesterday and since then I'm not able to log in KDE. Which is more strange is that it seems to have corrupted all library files related to X11, giving an error like this:

lib***.so.*: wrong ELF class: ELFCLASS32

I've reinstalled some packages and even the entire KDE with "apt-get install --reinstall", but this not solved everything. The X11 log is full of lines accusing the same error:

(==) Log file: "/var/log/Xorg.0.log", Time: Mon Aug  8 09:54:38 2011
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
dlopen: libdrm.so.2: wrong ELF class: ELFCLASS32
(EE) Failed to load /usr/lib/xorg/modules/extensions/libdri.so
(EE) Failed to load module "dri" (loader failed, 7)
dlopen: libdrm.so.2: wrong ELF class: ELFCLASS32
(EE) Failed to load /usr/lib/xorg/modules/extensions/libdri2.so
(EE) Failed to load module "dri2" (loader failed, 7)
dlopen: libdrm.so.2: wrong ELF class: ELFCLASS32
(EE) Failed to load /usr/lib/xorg/modules/drivers/nouveau_drv.so
(EE) Failed to load module "nouveau" (loader failed, 7)
dlopen: libdrm.so.2: wrong ELF class: ELFCLASS32
(EE) Failed to load /usr/lib/xorg/modules/drivers/nv_drv.so
(EE) Failed to load module "nv" (loader failed, 7)
dlopen: libdrm.so.2: wrong ELF class: ELFCLASS32
(EE) Failed to load /usr/lib/xorg/modules/drivers/vesa_drv.so
(EE) Failed to load module "vesa" (loader failed, 7)

The last entry on /var/log/syslog before that happen was:

Aug  8 09:03:05 biocomp-server kernel: [2423717.471034] __ratelimit: 26 callbacks suppressed
Aug  8 09:03:05 biocomp-server kernel: [2423717.471038] VirtualBox[3598]: segfault at 4589e046 ip 00007faeddee0920 sp 00007fff89475368 error 6 in libQtDBus.so.4.6.3[7faeddeb0000+77000]
Aug  8 09:03:05 biocomp-server kernel: [2423717.473469] polkitd[2308]: segfault at 8 ip 00007f6e717e18c8 sp 00007fff12170b38 error 4 in libpolkit-backend-1.so.0.0.0[7f6e717c7000+3e000]

Is there any way to solve that? Everything is still working but the X11.