Export LEF via problem

 Hi ,

While I trying to export .lef file from Cadence virtuoso 6.1.5 version , I got the following error p, li { white-space: pre-wrap; }

"ERROR: (OALEFDEF-50138): VIA Via56_stack_west: Failed to open master view - Open of gpdk180/Via56_stack_west/symbolic failed - cellView for the design was not found - Ensure that the via is correctly defined in the technology database."

Can anybody please solve this problem ?

Thanks & Regards,

Gangadhar.R