ArcGIS Raster Calculator error 000539 ImportError: No module named numpy?

I am running ArcGIS 10.2.1 on Win7 64bit. I have finished doing an NDVI, and after defining a vegetation presence threshold at 0.05, opened the Raster Calculator (via Map Algebra in the Arc Toolbox) to generate a new raster with a 0 value for no vegetation and a 1 value for vegetation. I'm getting the following error:

Executing: RasterCalculator ""NDVI_ik_06.tif" > 0.05"

ERROR 000539: Error running expression: rcexec() 
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in rcexec
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\__init__.py", line 24, in 
    from arcpy.toolbox import *
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\toolbox.py", line 356, in 

    from management import Graph, GraphTemplate
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\management.py", line 22, in 
    import _management
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\_management.py", line 14, in 
    import _graph
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\_graph.py", line 27, in 
    import numpy
ImportError: No module named numpy

Failed to execute (RasterCalculator).

Failed at Tue Apr 07 11:24:48 2015 (Elapsed Time: 0.09 seconds)

Any ideas?