AMD Radeon HD 6770 M Graphic Card (ADL_Overdrive6_FanSpeed_Get() is missing) Error

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My graphic card of my notebook is :
AMD Radeon HD 6770 M Graphic Card.

Commands in windows 7 64 bit - cmd :

oclHashcat64.exe -m 2500 c:\out.hccap c:\dic.txt

or

oclHashcat32.exe -m 2500 c:\out.hccap c:\dic.txt

Error after those commands :
ADL_Overdrive6_FanSpeed_Get() is missing

what is that error mean and how can i fix it?

thanks in advance