As Dana continues thrashing a road down the Civil 3D pipes path she managed to find another little gotcha in the export code. The images below should paint the the picture. I am posting an updated version that will deal with this as well.
Download the update here.
Ya, you gotta tell Excel not to autoformat those values as dates.
Usually I end up cutting and pasting into Notepad, saving as .txt then using the import wizard.
I *think* you can turn off the autodate “feature” in Excel.
Or you just hack the VBA to format those columns as text. Either way.