In certain situations, you can install SP2 for Land Desktop 2008, and the program will report that SP2 is installed, but in fact it is not really installed. I have confirmed this with Autodesk support. However, the exact circumstances regarding how this occurred has not been determined.
So how can you check to see if SP2 has really been applied? According to Autodesk support, you can test for SP2 by looking at the version of this file: C:\Program Files\AutoCAD Civil 3D Land Desktop Companion 2008\AeccAlnSvrLoader.dll. (Your path may vary) Read more about Land Desktop Service Pack Level