'.obj' is not a supported source type in BCB x64

Hi all,

I plan to convert our GPIB remote program from x86 to x64, but in BCB x64, '.obj' is not a supported source type (gpib-32.obj).
linker error:
[ilink64 Error] Error: Unresolved external 'ibdev' referenced from C:\C++PROJECT\CALIBRATOR_X64\WIN64\DEBUG\GPIB_CLASS.O
[ilink64 Error] Error: Unresolved external 'ibsta' referenced from C:\C++PROJECT\CALIBRATOR_X64\WIN64\DEBUG\GPIB_CLASS.O
[ilink64 Error] Error: Unresolved external 'ibonl' referenced from C:\C++PROJECT\CALIBRATOR_X64\WIN64\DEBUG\GPIB_CLASS.O
[ilink64 Error] Error: Unresolved external 'ibwrt' referenced from C:\C++PROJECT\CALIBRATOR_X64\WIN64\DEBUG\GPIB_CLASS.O
[ilink64 Error] Error: Unresolved external 'ibrd' referenced from C:\C++PROJECT\CALIBRATOR_X64\WIN64\DEBUG\GPIB_CLASS.O
[ilink64 Error] Error: Unresolved external 'ibcntl' referenced from C:\C++PROJECT\CALIBRATOR_X64\WIN64\DEBUG\GPIB_CLASS.O

It's there any other suggestion or replaceable resource?

Thanks and best regards,
Ann.