I have an ATI/AMD graphics card in my computer. However, every time I try to install the post-release updates, it always fails and deactivates the graphics driver.

I've pasted the last few messages following the ldconfig deferred processing now taking place message from the installation log from /var/log/jockey.log below; if you're interested, I have pasted the full output here.

WARNING: /sys/module/fglrx_updates/drivers does not exist, cannot rebind fglrx_updates driver
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx): target_alt /usr/lib/fglrx/ld.so.conf current_alt /usr/lib/fglrx/ld.so.conf other target alt /usr/lib/fglrx/alt_ld.so.conf other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: XorgDriverHandler(%s, %s).enabled(): No X.org driver set, not checking
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx): target_alt /usr/lib/fglrx/ld.so.conf current_alt /usr/lib/fglrx/ld.so.conf other target alt /usr/lib/fglrx/alt_ld.so.conf other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: XorgDriverHandler(%s, %s).enabled(): No X.org driver set, not checking
DEBUG: fglrx.enabled(fglrx): target_alt /usr/lib/fglrx/ld.so.conf current_alt /usr/lib/fglrx/ld.so.conf other target alt /usr/lib/fglrx/alt_ld.so.conf other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: XorgDriverHandler(%s, %s).enabled(): No X.org driver set, not checking
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx): target_alt /usr/lib/fglrx/ld.so.conf current_alt /usr/lib/fglrx/ld.so.conf other target alt /usr/lib/fglrx/alt_ld.so.conf other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: XorgDriverHandler(%s, %s).enabled(): No X.org driver set, not checking
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx_updates): target_alt None current_alt /usr/lib/fglrx/ld.so.conf other target alt None other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: fglrx_updates is not the alternative in use
DEBUG: fglrx.enabled(fglrx): target_alt /usr/lib/fglrx/ld.so.conf current_alt /usr/lib/fglrx/ld.so.conf other target alt /usr/lib/fglrx/alt_ld.so.conf other current alt /usr/lib/fglrx/alt_ld.so.conf
DEBUG: XorgDriverHandler(%s, %s).enabled(): No X.org driver set, not checking

What's going on? Is ldconfig corrupted, or has the driver package just not been properly installed, despite reporting to the "Additional Drivers" panel that it is?