使用TFS 2010运行PowerShell时出错

考虑到这个简单的脚本：

[void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.TeamFoundation.Client")
[void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.TeamFoundation.Build.Client")

$serverName="http://server:8080/tfs/Collection"
$tfs = [Microsoft.TeamFoundation.Client.TeamFoundationServerFactory]::GetServer($serverName)
$buildserver = $tfs.GetService([Microsoft.TeamFoundation.Build.Client.IBuildServer])

$buildServer.QueryBuildDefinitions("Project") | foreach {
  echo "Found build: $_.Name"
}

出现此错误的原因是什么：

Exception calling "QueryBuildDefinitions" with "1" argument(s): "Method not found: 'Boolean Microsoft.TeamFoundation.Client.TeamFoundationClientProxyBase.HandleUnauthorizedException(Microsoft.TeamFoundation.TeamFoundationServer
UnauthorizedException)'."
At C:\DevOps\TfsClient\Test.ps1:8 char:35
+ $buildServer.QueryBuildDefinitions <<<< ("Project") | foreach {
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException


$buildserver | Get-Member -Name QueryBuildDefinitions

   TypeName: Microsoft.TeamFoundation.Build.Client.BuildServer

Name                  MemberType Definition                                                                                                                                                                                        
----                  ---------- ----------                                                                                                                                                                                        
QueryBuildDefinitions Method     Microsoft.TeamFoundation.Build.Client.IBuildDefinition[] QueryBuildDefinitions(string teamProject), Microsoft.TeamFoundation.Build.Client.IBuildDefinition[] QueryBuildDefinitions(string teamP...

调用带有“1”参数的“QueryBuildDefinitions”时出现异常：“未找到方法：'布尔Microsoft.TeamFoundation.Client.TeamFoundationClientProxyBase.HandleUnauthorizedException（Microsoft.TeamFoundation.TeamFoundationServer
未经授权的例外情况。”
在C:\DevOps\TfsClient\Test.ps1:8 char:35
+$buildServer.QueryBuildDefinitions未经授权的部分可能有问题。您是否使用具有适当权限的帐户运行？我还将检查库的版本，以确保您正在加载您认为是的tfs对象的版本。
$buildServer | Get Member
列出
QueryBuildDefinitions（string teamProject）
未经授权的异常是可疑的。当你模仿的时候失败了吗？