running test lists fails with telerik.teststudio.scheduling.clientmachine error

running test lists have suddenly stopped working.
i get the attached error.

i made sure the scheduling server was connected and active. so not sure where to go form here.

also this in trace log:

05/07 14:10:21,Telerik.TestStudio.RemoteExecutor.exe(1444:9),Error] <>c__DisplayClass4.<RegisterResolver>b__1() : EXCEPTION! (see below)
     Situation: Exception trying to resolve dependency: Microsoft.TeamFoundation.Client, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
     Outer Exception Type: System.IO.FileNotFoundException
     Message: Could not load file or assembly 'Microsoft.TeamFoundation.Client, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
     HRESULT: 0x80070002 (Official ID (if app.) = 2147942402, Error Bit = FAILED, Facility = FACILITY_WIN32, Code = ERROR_FILE_NOT_FOUND)
     Call Stack:
          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.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 ArtOfTest.Common.BaseDependencyLoader.<>c__DisplayClass4.<RegisterResolver>b__1(Object o, ResolveEventArgs e)