HRESULT: 0x80070057 (E_INVALIDARG)

Very annoying problem for a good while today. I happened to be reverting my code back to a previous version of the repository on SVN. We needed to roll back some changes, and to my surprise after going back to the previous version I wasn't able to build the solution anymore, showing me a weird error:
"Could not load file or assembly … The parameter is incorrect … HRESULT: 0x80070057 (E_INVALIDARG)".