When I attempt to login to umbraco on our staging version of the site I am greeted with a little red box that says:

Server error: Contact administrator, see log for full details.
Server call failed for checking authentication

And then in the trace log I have the following error:

2014-01-29 15:18:28,955 [128] ERROR Umbraco.Core.PluginManager - [Thread 122] Error creating type Umbraco.Core.Models.PublishedContent.PublishedPropertyType+CompatConverter
System.MissingMethodException: No parameterless constructor defined for this object.
   at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck)
   at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
   at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(Type type, Boolean nonPublic)
   at System.Activator.CreateInstance(Type type)
   at Umbraco.Core.PluginManager.CreateInstances[T](IEnumerable`1 types, Boolean throwException)

I'm running version 7.0.1 assembly: 1.0.5095.27251

I'm developing locally on my machine and the site will run perfectly fine for me. Launching it from visual studio using iis express. The backoffice was working yesterday, and I haven't made any changes to anything other than css files today. I have been deploying to staging using visual studio's built in publish functionality.

I have tried manually deploying the files as well, still cannot get the backoffice login to load. The front end is all still working perfectly.

I'm not having any luck searching the forums and searching on google in general, if anyone has any ideas or knows of a solution it would be most appreciated.