From this thread http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Geo
I did the uninstall and afterwards opening Civil 3D gave me a message about an error loading a code on line something or other(guess I should have written it down?). I would ok it and things seemed ok, except for a couple of fatal error crashes. After several incidents, I did a repair on the Civil 3D install, and now no error on loading and no crashes.
If you do the uninstall, do a repair on your Civil 3D and restart.
We are pleased to announce the release of Geotechnical Module v1 for both Civil 3D 2013 and Infrastructure Design Suite 2014.
These are now available for download on Subscription Center along with release notes. Please uninstall any previous version of the Geotechnical Module prior to installing Geotechnical Module v1.
For the 2013 version, you will find it listed under Civil 3D Productivity Tools. For 2014, you will need to have either IDS Premium or IDS Ultimate and chose to "View All Product Enhancements". Then you will see the Geotechnical Module listed as a link. When you click that link, the page with the updated downloads will appear.
Let me know if you still can't find it, I can see it when I log in with a simulated customer account.
A good start - no idea what this means or how to get around it...
Can you tell me when this is appearing? Is it as you install the geotechnical module or is it a specific command you are using?