Could not load file or assembly ‘AjaxControlToolkit’ or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0×80070057 (E_INVALIDARG))

I’m running Vista and have no “C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files” folder, but I did find “C:\Users\DellUser\AppData\Local\Temp\Temporary ASP.NET Files”. Clearing this folders contents corrected my build error