WAC and Lync 2013 server - 'Error in /m'

[AWS]

I have successfully integrated Office Web App Server with my SharePoint 2013, and Exchange 2013 servers, I'm right now trying to get integration between Lync 2013 and Office Web App server going, but i'm encountering an error when trying to present powerpoint
documents.
"Some sharing features are unavailable due to server connectivity issues"
I can confirm that LS Data MCU event IT 41032 on the Lync Server, and have restarted my Lync FE server. On the WAC Server I'm noticing the following error occurs when trying to share a powerpoint:
Event code: 3008
Event message: A configuration error has occurred.
Event time: 2/7/2013 9:41:30 AM
Event time (UTC): 2/7/2013 5:41:30 PM
Event ID: 3808d0e3d8674543807c3d304f4412e5
Event sequence: 1
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/2/ROOT/m-10-130047324907416215
Trust level: Full
Application Virtual Path: /m
Application Path: Crogram FilesMicrosoft Office Web AppsBroadcastServices_Host
Machine name: OWA

Process information:
Process ID: 1820
Process name: w3wp.exe
Account name: NT AUTHORITYNETWORK 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. (Crogram FilesMicrosoft Office Web AppsBroadcastServices_Hostweb.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: https://office.somedomain.com:443/m/ParticipantFrame.aspx?a=0&e=true&
Request path: /m/ParticipantFrame.aspx
User host address: xx.xx.xx.xx
User:
Is authenticated: False
Authentication Type:
Thread account name: NT AUTHORITYNETWORK SERVICE

Thread information:
Thread ID: 39
Thread account name: NT AUTHORITYNETWORK 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:

accessing the URL directly
https://office.somedomain.com:443/m/ParticipantFrame.aspx?a=0&e=true& also returns the "error in /m"

any advise?

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