I just downloaded the source version of DNN 5.2.  I am currently developing on Visual Studio 2005.  When I tried to compile the DNN 5.2 library project, I got syntax errors.  One of the errors happened in ModuleInfo.vb with this code:

  effectiveCacheMethod = (From provider In ModuleCache.ModuleCachingProvider.GetProviderList() _
                                        Where provider.Value.Equals(defaultModuleCache) _
                                        Select provider.Key).SingleOrDefault

The compiler complained that "from is not declared".  It appears that this is a LINQ statement, although I am not sure.  I am not really familiar with LINQ.  Do I need to add any kind of special reference or update to my project so that VS 2005 recognizes this?  I am running the latest version of the .NET framework on my system (3.5 SP1).  I had also tried explicitly adding the reference System.Data.Linq, but that didn't seem to work either.    I have had to make some custom changes to the DNN library to suit my company's needs, which is why I need to recompile for 5.2 to include my customizations.  Has anyone else run into this issue?