Non-zero error with ImportFromEPSG() in GDAL/OSR/Python

Question

I'm currently getting an error when testing ImportFromEPSG() on my GDAL.

import osr
testSR = osr.SpatialReference()
testSR.ImportFromEPSG(4326)
#this returns value of 6
print testSR.ExportToPrettyWkt()
#this returns blank/empty string

I have GDAL_DATA in os.evirons set to C:\Program Files\GDAL\gdal-data, which is where gcs.csv is located. The proj.dll file is in C:\Program Files\GDAL. Running 'GDAL_DATA' in os.environs returns TRUE.

Any suggestions?

I consulted this past link but it did not lead to a solution for me.