Office Web Apps 2013 - Warning: Event code: 3008 - Event ID: 1310

Hi,

i've installed a fresh version of office web apps RTM and connected it successfull with my sharepoint 2013 RTM farm. So far so good.

But if i try to get a preview in sharepoint, it takes quite long (10-15sec) and i found this message on owa-server:

Event code: 3008 
Event message: A configuration error has occurred. 
Event time: 01.11.2012 08:44:30 
Event time (UTC): 01.11.2012 07:44:30 
Event ID: 2a60d040d2d246c886a897ad758c7c5d 
Event sequence: 1 
Event occurrence: 1 
Event detail code: 0 
Application information: 
    Application domain: /LM/W3SVC/2/ROOT/m-658-129962294709223339 
    Trust level: Full 
    Application Virtual Path: /m 
    Application Path: C:\Program Files\Microsoft Office Web Apps\BroadcastServices_Host\ 
    Machine name: OWA01
Process information: 
    Process ID: 6056 
    Process name: w3wp.exe 
    Account name: NT AUTHORITY\NETWORK SERVICE 
Exception information: 
    Exception type: ConfigurationErrorsException 
    Exception message: Could not load file or assembly 'Microsoft.Build.Utilities, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. (C:\Program Files\Microsoft Office Web Apps\BroadcastServices_Host\web.config line 44)
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)
   at System.Web.Configuration.AssemblyInfo.get_AssemblyInternal()
   at System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig)
   at System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath)
   at System.Web.Compilation.BuildManager.ExecutePreAppStart()
   at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException)

Could not load file or assembly 'Microsoft.Build.Utilities, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
   at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean forIntrospection)
   at System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
   at System.Reflection.Assembly.Load(String assemblyString)
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)

 
 
Request information: 
    Request URL: http://owa01/m/GetData.ashx?health=1 
    Request path: /m/GetData.ashx 
    User host address: fe80::6d1e:6301:a909:dc1aC:\Program Files\Microsoft Office Web Apps\BroadcastServices_Host\ 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: NT AUTHORITY\NETWORK SERVICE 
 
Thread information: 
    Thread ID: 14 
    Thread account name: NT AUTHORITY\NETWORK SERVICE 
    Is impersonating: False 
    Stack trace:    at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)
   at System.Web.Configuration.AssemblyInfo.get_AssemblyInternal()
   at System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig)
   at System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath)
   at System.Web.Compilation.BuildManager.ExecutePreAppStart()
   at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException)
 
 
Custom event details: 

What does this mean?

The part of the BroadCastServices_Host webconfig looks like this:

<system.web><customErrors mode="On" defaultRedirect="/error.html"/><compilation debug="false"><assemblies><add assembly="Microsoft.Build.Utilities, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/><add assembly="Microsoft.Build.Framework, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/></assemblies></compilation><!-- This is set to false for security reasons --><trace enabled="false"/></system.web>

It's "only" a warning log, but i think it's not normal or a feature ;)

The Web-Apps Server is joind to the same domain, the sharepoint server is. Both running Windows Server 2012.

Thx for your help!