Could not load file or assembly 'DotnetAgentHttpModule, Version=3.2.3.232

I have a number of .Net web applications hosted on Windows Server 2008 R2 Standard running IIS 7.5. Loading each application throws the following exception:

Exception information: 
    Exception type: ConfigurationErrorsException 
    Exception message: Could not load file or assembly 'DotnetAgentHttpModule, Version=3.2.3.232, Culture=neutral, PublicKeyToken=2311bd8fc83e4f7c' or one of its dependencies. The system cannot find the file specified.
   at System.Web.Configuration.ConfigUtil.GetType(String typeName, String propertyName, ConfigurationElement configElement, XmlNode node, Boolean checkAptcaBit, Boolean ignoreCase)
   at System.Web.Configuration.ConfigUtil.GetType(String typeName, String propertyName, ConfigurationElement configElement, Boolean checkAptcaBit, Boolean ignoreCase)
   at System.Web.Configuration.ConfigUtil.GetType(String typeName, String propertyName, ConfigurationElement configElement, Boolean checkAptcaBit)
   at System.Web.Configuration.Common.ModulesEntry.SecureGetType(String typeName, String propertyName, ConfigurationElement configElement)
   at System.Web.Configuration.Common.ModulesEntry..ctor(String name, String typeName, String propertyName, ConfigurationElement configElement)
   at System.Web.HttpApplication.BuildIntegratedModuleCollection(List`1 moduleList)
   at System.Web.HttpApplication.GetModuleCollection(IntPtr appContext)
   at System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers)
   at System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context)
   at System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context)
   at System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext)

The assembly referenced is not from our applications, and the stack trace suggests it is a Microsoft assembly but googling this specific name gives no hits. I have the same version of the same applications hosted on identical servers all working fine so I'm fairly sure the applications themselves aren't the problem. I've tried recycling the respective app pools, restarting IIS, deleting the temporary ASP.Net files, redeploying the applications, rebooting and reinstalling the .Net framework. There have been no changes to the server hardware or software recently as far as I know. Can anyone suggest what may be the cause of this exception?