看他们好多人遇到这个问题 我也遇到了，而且半天没解决啊  百度谷歌搜索了一大圈

基本解决方案是什么根目录下放crossdomain.xml文件

内容为如下

<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-access-from domain="*" headers="*" secure="false"/>
</cross-domain-policy>

　结果我发现了错误依然存在，突然看到了有一篇文章使用完全的路径我试了下嘿 还真可以上代码

<input id="fileupload1" class="mini-fileupload" name="FSelect" limittype="*.xls;*.xlsx" uploadurl="../../DynamicForm/UserInformation/Excel_DR.aspx" flashurl="../../swfupload/swfupload.swf" onuploadsuccess="onUploadSuccess" onuploaderror="onUploadError" />

　　上图是我的源代码 改为如下就可以了

<input id="fileupload1" class="mini-fileupload" name="FSelect" limittype="*.xls;*.xlsx" uploadurl="http://IP:端口/DynamicForm/UserInformation/Excel_DR.aspx" flashurl="http://IP:端口/swfupload/swfupload.swf" onuploadsuccess="onUploadSuccess" onuploaderror="onUploadError" />

　　问题到此成功解决~