...fatto, e ora è cambiato il tipo di errore:

(WW) fglrx: No matching Device section for instance (BusID PCI:1:0:1) found
*** If unresolved symbols were reported above, they might not
*** be the reason for the server aborting.

Fatal server error:
Caught signal 8. Server aborting


When reporting a problem related to a server crash, please send
the full server output, not just the last messages.
This can be found in the log file "/var/log/XFree86.0.log".
Please report problems to xfree86@xfree86.org.
Però ora il servere era quasi partito, mentre prima non partiva nemmeno!