I realize that CMultiFileUpload allows me to upload multiple files at once, but I want the user to be able to select multiple files at one time when they click the Browse button. I used htmlOptions to add multiple=multiple to the input tag and it does allow the user to select more than one file, however only one file is uploaded.
CMultiFileUpload is based on jQuery Multiple File Upload Plugin which support single selection at a time. Please try "xupload" - jquery file upload extension for yii, it will solve your problem.