I just downloaded and installed Events 4.0.1 on my localhost test machine and got the following when adding the module to a page, I am running DNN 4.8.2:
Error: Events is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: C:\WINNT\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\dotnetnuke\d7ebc37e\bb994470\App_Web_eventmonth.ascx.1cabaa39.ynvk5dot.0.vb(459): error BC32206: Indirect reference is being made to assembly DotNetNuke.Events.WebControls version 4.0.1.25579, which contains 'DotNetNuke.Modules.Events.EventMonth.EventCalendar'. This Project references a prior version of DotNetNuke.Events.WebControls version 3.3.8.14424. To use 'DotNetNuke.Modules.Events.EventMonth.EventCalendar', you must replace the reference to DotNetNuke.Events.WebControls with version 4.0.1.25579 or higher. ---> System.Web.HttpCompileException: C:\WINNT\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\dotnetnuke\d7ebc37e\bb994470\App_Web_eventmonth.ascx.1cabaa39.ynvk5dot.0.vb(459): error BC32206: Indirect reference is being made to assembly DotNetNuke.Events.WebControls version 4.0.1.25579, which contains 'DotNetNuke.Modules.Events.EventMonth.EventCalendar'. This Project references a prior version of DotNetNuke.Events.WebControls version 3.3.8.14424. To use 'DotNetNuke.Modules.Events.EventMonth.EventCalendar', you must replace the reference to DotNetNuke.Events.WebControls with version 4.0.1.25579 or higher. at System.Web.Compilation.AssemblyBuilder.Compile() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath) at System.Web.UI.TemplateControl.LoadControl(String virtualPath) at DotNetNuke.Modules.Events.Events.LoadModuleControl() --- End of inner exception stack trace ---