Hi Ha,
What type of PERC check are you running?
Is it an LDL High-Level Check? If so, open the Calibre PERC User's Manual and go to this section:
High-Level Checks and Topological DRC > High-Level Check Types > Performing a High-Level Check
The instructions discuss a VOLTAGE_AWARE_DRC check, but the flow is pretty much the same for any of the LDL checks.
Assuming it is an LDL check, you can find the name of the output database to load from the DFM DATABASE statement in the rules.
dan