After attempting to install uBlogsy (the install failed), many scripts are failing in my production environment, with the following error shortly after the server starts up being my only clue:

Can't import MacroEngine 'umbraco.MacroEngines.RazorMacroEngine': System.ArgumentException: An item with the same key has already been added.

   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)

   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)

   at umbraco.cms.businesslogic.macro.MacroEngineFactory.getEngines(List`1 types)

What could be causing this, and how do I fix it?  We are running Umbraco 4.7.2 with asp.net 4.0