ArcHydro 2.0 MSI installer -- Error 1606 when Python26 not in default ESRI location

Discussion created by vsfoote Champion on Oct 22, 2011
Dean D., et. all

Has anyone worked out the command line, or MSI installer edits in Orca, needed to install ArcHydro (or HEC-GeoHMS) when Python26 is installed to a location other than ESRI's C:\Python26\ArcGIS10.0 location?

I have an existing Python26 installation to the Python.org default C:\Python26 location, and ArcHydro installer is throwing ERROR 1606. Could not access network location ArcGIS10.0. Also seeing a related installer issue that, lacking the Python26 default location, if a large data drive (D:\) is present--the installer defaults to a TARGETDIR of D:\

Looking through the .msi installer the ESRI default location looks to be hardcoded in:
[INDENT]CustomAction --> SetPythonHome: Source PYTHONHOME: [PYTHONDIR]ArcGIS10.0
(which is the default ArcGIS Desktop10.0 Python install location ESRI uses)[/INDENT]

For the Desktop10.0 install we can use the INSTALLDIR1= command line value to specify the Python26 install location. But I can't figure a similar configuration out for the ArcHydro package install.