My arcgis has some sort of incompatibility with python. Even for the simplest task on the raster calculator I keep getting the same error - error 000539: error running expression:rcexec() : no module named os. Also, all routines on the arctoolbox that are python scrips simply do not work. I already had python 27 (for SPSS) previous to installing arcgis 10.0, but it installed python 26 and everything else seems to work fine. Is there anything I can do to solve this?