Setting the geoprocessor's OverwriteOutput property from a Python script does not seem to work

[jjr8]

In the script below, if the files in inputFiles has already been copied to outputFiles, the script will fail with an error indicating that a destination file already exists. This is not supposed to happen because the geoprocessor's OverwriteOutput? environment variable is supposed to be used by FileFindAndCopy?_GeoEco to determine whether files should be overwritten.

from win32com.client import Dispatch

gp = Dispatch('esriGeoprocessing.GPDispatch')
gp.AddToolbox('c:\\Python25\\lib\\site-packages\\GeoEco\\ArcGISToolbox\\Marine 
print(str(gp.OverwriteOutput))
gp.OverwriteOutput = True
print(str(gp.OverwriteOutput))
gp.FileFindAndCopy_GeoEco('c:\\temp8\\inputFiles', 'c:\\temp8\\outputFiles')

The print statements show that the OverwriteOutput? environment variable is being set. But enabling debug logging reveals that FileFindAndCopy?_GeoEco apparently is not seeing the True value:

2007-06-19 14:28:41,415 DEBUG ArcGIS Geoprocessor object 0x00EB0E90: Get OverwriteOutput returned False
2007-06-19 14:28:41,415 DEBUG Parameter overwriteExisting = False

At first glance, this looks like a bug in Arc 9.1.