Recently I upgraded our site to version 9 and also applied recent security patches.

In the past we had replaced our registration page with one that used a better captcha in order to avoid fake registrations.

Now the registration page isn't working at all, and the following message is in the logs:

2017-07-15 00:06:37,945 [snow][Thread:24][ERROR] DotNetNuke.UI.Modules.ModuleHost - System.Web.HttpParseException (0x80004005): The type 'DotNetNuke.Modules.Admin.Users.Register' is ambiguous: it could come from assembly 'd:\sites\[snip]\home\bin\DotNetNuke.Website.DLL' or from assembly 'd:\sites\[snip]\home\bin\iwebs.Modules.Register.DLL'. Please specify the assembly explicitly in the type name. ---> System.Web.HttpParseException (0x80004005): The type 'DotNetNuke.Modules.Admin.Users.Register' is ambiguous: it could come from assembly 'd:\sites\[snip]\home\bin\DotNetNuke.Website.DLL' or from assembly 'd:\sites\[snip]\home\bin\iwebs.Modules.Register.DLL'. Please specify the assembly explicitly in the type name. ---> System.Web.HttpException (0x80004005): The type 'DotNetNuke.Modules.Admin.Users.Register' is ambiguous: it could come from assembly 'd:\sites\[snip]\home\bin\DotNetNuke.Website.DLL' or from assembly 'd:\sites\[snip]\home\bin\iwebs.Modules.Register.DLL'. Please specify the assembly explicitly in the type name.

at System.Web.UI.Util.GetTypeFromAssemblies(IEnumerable assemblies, String typeName, Boolean ignoreCase)

at System.Web.UI.TemplateParser.GetType(String typeName, Boolean ignoreCase, Boolean throwOnError)

at System.Web.UI.TemplateParser.ProcessInheritsAttribute(String baseTypeName, String codeFileBaseTypeName, String src, Assembly assembly)

at System.Web.UI.TemplateParser.PostProcessMainDirectiveAttributes(IDictionary parseData)

at System.Web.UI.TemplateParser.ProcessException(Exception ex)

at System.Web.UI.TemplateParser.ParseStringInternal(String text, Encoding fileEncoding)

at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding)

at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding)

at System.Web.UI.TemplateParser.ParseFile(String physicalPath, VirtualPath virtualPath)

at System.Web.UI.TemplateParser.Parse()

at System.Web.Compilation.BaseTemplateBuildProvider.get_CodeCompilerType()

at System.Web.Compilation.BuildProvider.GetCompilerTypeFromBuildProvider(BuildProvider buildProvider)

at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders()

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, Boolean throwIfNotFound, Boolean ensureIsUpToDate)

at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)

at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean ensureIsUpToDate)

at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath)

at DotNetNuke.UI.ControlUtilities.LoadControl[T](TemplateControl containerControl, String ControlSrc)

at DotNetNuke.UI.Modules.WebFormsModuleControlFactory.CreateModuleControl(TemplateControl containerControl, ModuleInfo moduleConfiguration)

at DotNetNuke.UI.Modules.ModuleControlFactory.LoadModuleControl(TemplateControl containerControl, ModuleInfo moduleConfiguration)

at DotNetNuke.UI.Modules.ModuleHost.LoadModuleControl()

What can I do to re-enable registration?