服务器上动态生成的文件不会在Windows Server 2003上释放进程句柄.NET

I have build a web application which the user can request a report which is generated on the server and sent back to the client. The process works fine and sends the file back to the client, however we are unable to open the file. Further investigation reveals that a process on the server still has a handle on the file by the IIS Application Pool.I have build a web application which the user c