I am getting the same (BC30451: Name 'Config' is not declared) error that is apparently fairly common, but none of the published solutions are working.  I have searched extensively on Google, asp.net, and here in both the blogs and forums - the answer is clearly to rename the release.config file.  I have tried that and it does not work.  I am attempting a brand-new install of DNN 4.5.1 and have tried replacing my web.config file with the release.config from the Install download and from the StarterKit download.  Neither file (which are identical) resolved the issue.  According to my text editor's file compare function, the web.config file is identical to the release.config file in these zipped downloads, but I am replacing it anyway - to no avail.  I have replaced my web.config file from numerous sources multiple times each - each time correcting my SQL/CustomError/databaseowner settings before uploading the new copy to the server, and I continue to get the same error.  I have not been using the SourceFile download so it is not a "compile the binaries" issue.

I would appreciate someone offering another possibility for me to check to help get past this error.

See if you can get any asp.net 2.0 websites working first.

Please someone offer an idea - I can't seem to get past this one issue.  My .Net test scripts work without web.config, but they generate the same error with the web.config in the root as DNN does.  What other possibilities can I check?