Error in early rail analysis in Cadence EPS

I am trying to do the early rail analysis of a design in Encounter Power System tool. I imported the placement completed design, generated the power grid library and set the rail analysis mode to be static. While doing the static rail analysis, the execution stops with a message:

* Exiting vstorm2 normally.
vstorm2 exited unsuccessfully.
Check Reports/main.html generated inside state directory.

There are no files created in the Reports folder too. Prior to the termination of the analysis, I was getting two more error messages as follows:

ERROR (EXTZX-133) : Could not find any shapes to perform parasitic extraction on the selected
nets. Therefore, the extraction tool can not produce output data. Most
likely, program could not match net names specified in the command file to
the net names the design data. Otherwise, selected nets do not associate
with geometry data (routing or pin). So, check the design data for those
nets.

*** Error: In file /tmp/vstorm_13960.cmd at line number 27 :-
R extraction failed.

I could not find the /tmp/ folder in my current directory. VDD and VSS were the defined rails in the EDI design for placement. What could be possible reason for these errors?