I gave that a go, but it does not build the packages. Perhaps because of differences between Lenny and Squeeze? It did not seem to find things where it was looking for them (looking in /lib/X11R6/lib86, which does not exist).

I have continued playing around with the Ubuntu manual solution I mentioned before and managed to tweak it for Debian (kludged the kludge: I need a shower). I have managed to build 8.12 against the current kernel and installed the package. Things still do not seem to work, however. If I reboot with the xorg.config file set for ATI, X fails to load with errors of the driver not existing. Seems obvious enough: make sure the module is loaded.

Code:

$ sudo modprobe fglrx
FATAL: Error inserting fglrx (/lib/modules/2.6.26-2-amd64/misc/fglrx.ko): Cannot allocate memory

Code:

$ dmesg
(...SNIP...)
[   68.225514] fglrx: module license 'Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY' taints kernel.
[   68.271664] [fglrx] Maximum main memory to use for locked dma buffers: 2870 MBytes.
[   68.271664] [fglrx:drm_alloc] *ERROR* [driver] Allocating 0 bytes
[   68.271664] [fglrx:firegl_init_device_list] *ERROR* Out of memory when allocating device heads
[   68.271664] [fglrx:firegl_init_module] *ERROR* firegl_init_devices failed

I only use about 5% of my memory, so I doubt I am out. Reading around on Google, I found references to this issue with older cards, but mine is fairly recent and this is the same source as the module I used perfectly fine all year.

I have currently reverted to the default xorg.config (not using the fglrx driver). The low res is ugly, but at least I can copy errors across to Iceweasel.