Exchange 2013 cu1 crashes on step 4 for Unified Messaging

Mailbox role: Unified Messaging service                                                           FAILED
     The following error was generated when "$error.Clear();
          $lochost=hostname;
          $ums=Get-UMService -Identity $lochost -DomainController $RoleDomainController;
          Set-UMService $ums.Identity `
          -DomainController $RoleDomainController `
          -IrmLogPath ($RoleInstallPath + "\Logging\IRMLogs") `
          -IrmLogMaxDirectorySize 262144000 `
          -IrmLogMaxFileSize 10485760 `
          -IrmLogEnabled $true
        " was run: "The term 'hostname' is not recognized as the name of a cmdlet, function, script file, or operable pr
ogram. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.".

     The following error was generated when "$error.Clear();
          $lochost=hostname;
          $ums=Get-UMService -Identity $lochost -DomainController $RoleDomainController;
          Set-UMService $ums.Identity `
          -DomainController $RoleDomainController `
          -IrmLogPath ($RoleInstallPath + "\Logging\IRMLogs") `
          -IrmLogMaxDirectorySize 262144000 `
          -IrmLogMaxFileSize 10485760 `
          -IrmLogEnabled $true
        " was run: "Cannot convert 'System.Object[]' to the type 'Microsoft.Exchange.Configuration.Tasks.UMServerIdParam
eter' required by parameter 'Identity'. Specified method is not supported.".