NuGet Assembly outside lib folder

I just ran into this problem. Nuget is expecting a structure that looks like:

root
  - lib
    - net40
      - File1.dll
      - File2.dll
      - File3.dll

net40 or net20 or net45 as appropriate to your .net version.

run

nuget pack yourlibrary.nuspec

to package it up.

That will pack up the dir wholesale and put it in the nupkg. The error messages will disappear at that point.