Import psspy returns error: DLL load failed

edit

I have installed PSS34. The installation GUI has installed Python 2.7 and I have included that address in my code.

import os
import sys
import xlwt
import xlrd
import scipy.io

# Importing the psspy run PSSE
PSSE_LOCATION = r"C:\Program Files (x86)\PTI\PSSEXplore34\PSSPY27"
sys.path.append(PSSE_LOCATION)
os.environ['PATH'] = os.environ['PATH'] + ';' + PSSE_LOCATION
print('sys.path')
import psspy

The Python code is called within MATLAB and psspy.pyc exists in PSSPY27 folder. But it returns the following error:

File ".\psspy.py", line 56, in <module> ImportError: DLL load failed: The specified module could not be found.