In my continued attempts to solve the Landis.RasterIO.Gdal issue, I downloaded the source for the LSML. The url for this library is https://code.google.com/p/landis-spatial/. this url should be accessed through a web browser, not Tortoise SVN. The url to actually checkout the code is svn checkout http://landis-spatial.googlecode.com/svn/trunk/ landis-spatial-read-only.
I also tried creating a simple project referencing the installed Landis libraries as recommended by the message boards. This worked for a few minutes but then broke again with the same error. So strange! Have you ever felt like you're walking in circles? The key seems to be the gdal_csharp.dll but I'm not sure where this file should be put or how it should be used.