Full exception .. 

Exception information: 
    Exception type: HttpParseException 
    Exception message: d:\My Developments\UMBRACO\v4.5.1_for_net_3_5\build\umbraco\controls\Tree\TreeControl.ascx(60): error CS0103: The name 'GetLegacyIActionJavascript' does not exist in the current context 

Request information: 
    Request URL: http://localhost/umbraco/default.aspx 
    Request path: /umbraco/default.aspx 
    User host address: ::1 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: IIS APPPOOL\Umbraco4.5.1 

Thread information: 
    Thread ID: 24 
    Thread account name: IIS APPPOOL\Umbraco4.5.1 
    Is impersonating: False 
    Stack trace:    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.ParseFile(String physicalPath, VirtualPath virtualPath)
   at System.Web.UI.TemplateParser.ParseInternal()
   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)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile)
   at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean noAssert)
   at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp, Boolean noAssert)
   at System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.HttpApplication.MapIntegratedHttpHandler(HttpContext context, String requestType, VirtualPath path, String pathTranslated, Boolean useAppConfig, Boolean convertNativeStaticFileModule)
   at System.Web.HttpServerUtility.Execute(String path, TextWriter writer, Boolean preserveForm)

got the same problem,
copying the 4.5.1 bin folder from the download once again did the trick for me

Thanks Bram, I did that and it enabled me to get back in, but when trying to media it errors again.

So it's not really a solution. :( 

on a win2008 server I don't get the GetLegacyIActionJavascript but now I get an empty tree.
treeWindow_content stays empty without any javascript errors :(

POST http://basis.webs.be/umbraco/webservices/TreeClientService.asmx/GetInitAppTreeData
301 Moved Permanently
GET http://basis.webs.be/umbraco/webservices/treeclientservice.asmx/getinitapptreedata
500 Internal Server Error

this are the console errors I get

I'm getting the same error

Error 393 The name 'GetLegacyIActionJavascript' does not exist in the current context c:\Projects_IGT.com\Umbraco\Web\umbraco\controls\Tree\TreeControl.ascx 60 

 trying to compile the the whole thing with Umbraco/umbraco folder in it...

Any ideas ?

What server are you running on?
We got this problem on a new Win2008Server and we solved this problem by uninstalling and reinstalling IIS7 again.

Hope this will help you.

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