I went through the "Solid Edge ST Addins - Part I" article and made the c++ project in Visual Studio Professional 2008.  The project compiled, but the linking was not sucessful.  I received the following error message:

1>Linking...
1>   Creating library Debug\L.lib and object Debug\L.exp
1>LAddin.obj : error LNK2001: unresolved external symbol _CATID_SEApplication
1>Debug\L.dll : fatal error LNK1120: 1 unresolved externals

Commenting out the following code will eliminate the linking error, but I still don't understand why this causes the linking error and I may very well want to handle a specific environment.

/* If you need to handle a specific environment, do the following. */

    if (IsEqualCLSID(clsidEnv, CATID_SEApplication))
    {
        /* Do something specific for this environment. */
    }

Anyone have any idea how to properly fix this linking error?  Thanks.