我无法从webdriver上传Target.xls文件。我提供了正确的语法。语法如下。程序执行正常，但不上传文件。
错误：
> Error in console: "uploaders[activeUploader].upload(...) is undefined
> [reported to Rollbar]"
代码：
driver.findElement(By.cssSelector("#ad-import .file-upl .btn-upload input:nth-of type(1)")).sendKeys("C:\\Eclipse\\Im\\Target.xls");
页：
<div id="ad-import" class="modal hide in" style="display: block;" data-type="ADS">
<div class="modal-header">
<div class="modal-body">
<div class="modal-body-inner spr">
<div class="inst-screen">
<div class="temp-screen"></div>
<div class="data-screen">
<div class="radio-grp scp clearfix btn-grp weak">
<div class="upload-container file-upl" data-uploader="FILE">
<section class="file-upload spr sections active" data-type="FILE">
<div class="file-drag-container">
<div class="file-drag-area">
</section>
<section class="file-paste hide sections" data-type="TEXT">
</div>
<div class="upload-container img-upl" data-uploader="IMAGE">
<div class="txt scp">
<div class="spr img-upl-cnt">
</div>
</div>
</div>
</div>
<div class="modal-footer">
<a class="btn lfloat template" href="/ui/rest/pi/import/sampleFile?channelType=applr&importType=amns">Download Template</a>
<div class="btn btn-primary rfloat btn-upload-pub splmin" data-loading-text="Importing..." data-action="upload">Import</div>
<div class="btn rfloat" data-action="cancel">Cancel</div>