the same bug here; when i added a second card to system aticonfig fails to get the clocks from both cards. however with one card it was all working, and only get clocks is not working. set clocks, get temperature, everything else is working... i reinstalled & updated catalyst to 11.8 - nothing changed so. the even strangest thing is that atitweak show everything ok.
linux-freepc:~ # aticonfig --adapter=all --odgt
Adapter 0 - ATI Radeon HD 5800 Series
Sensor 0: Temperature - 42.50 C
Adapter 1 - ATI Radeon HD 5800 Series
Sensor 0: Temperature - 47.50 C
linux-freepc:~ # aticonfig --adapter=all --odgc
ERROR - Get clocks failed for Adapter 0 - ATI Radeon HD 5800 Series
ERROR - Get clocks failed for Adapter 1 - ATI Radeon HD 5800 Series
linux-freepc:~ # atitweak -s
0. ATI Radeon HD 5800 Series (:0.0)
engine clock 157MHz, memory clock 300MHz, core voltage 0.95VDC, performance level 0, utilization 0%
fan speed 21% (1112 RPM) (default)
temperature 42.5 C
1. ATI Radeon HD 5800 Series (:0.1)
engine clock 600MHz, memory clock 900MHz, core voltage 1.063VDC, performance level 0, utilization 0%
fan speed 22% (1273 RPM) (default)
temperature 47.5 C