In Raster Calculator using:
(FocalSt_meanDEMtif5-FocalSt_minDEMtif1) / (FocalSt_maxDEMtif2-FocalSt_minDEMtif1)
What is the meaning of
ERROR 000539: Error running expression: rcexec() : No module named os
This error is discussed in an Esri Technical Article entitled Error: ERROR 000539: Error running expression: rcexec() which says:
This error is due to Raster Calculator not being exposed to Python as a tool. Currently, Raster Calculator is only exposed as a geoprocessing tool in ArcGIS or in ModelBuilder. However, there are a number of different ways to use Raster Calculator functions in Python.