Exchange 2010 SP1 Upgrade fails on CAS role

I am busy upgrading our Exchange 2010 servers to SP1 and two servers were successfully updated, the third server fails on the CAS role which fails with the following error

Exchange Server component Client Access Role failed.
Error: Error:
The following error was generated when "$error.Clear();
          $CommandAppCmd = join-path $env:SystemRoot System32\inetsrv\appcmd.exe;
          $imagePath = [System.IO.Path]::Combine($RoleInstallPath, "ClientAccess\Owa\auth\exppw.dll");
          Start-SetupProcess -Name "$CommandAppCmd" -args "install module /name:exppw /image:`"$imagePath`" /add:false" -IgnoreExitCode @(183);
          Start-SetupProcess -Name "$CommandAppCmd" -args "add module /name:exppw /app.name:`"Default Web Site/owa`"" -IgnoreExitCode @(183);
        " was run: "Process execution failed with exit code 1346.".
 
Process execution failed with exit code 1346.


Any help would be appreciated