When calling pyxll.plot, depending on the type of chart you are trying to show, PyXLL will use an ActiveX web control to display the chart.
If you have ActiveX controls disabled creating the ActiveX web control will fail and you will see this error in your log file:
ERROR : An error occurred when attempting to show a plot in Excel: Exception raised calling Add: Cannot insert object. (0x800a03ec, code=0x3ec, facility=0xa, severity=0x1)
To fix this you need to enable ActiveX controls in your Excel Options. Go to Options in Excel, then "Trust Center" and select "ActiveX Settings" on the left hand side. Then enable all controls to allow the ActiveX web control to be created.
