I have working on an application which needs to read the data from the excel. so i used the microsoft.office.interop.excel.dll in my application using add reference.That is working fine on my development environment and my development environmenthas winxp. Now when i want to host that application on my host server that have win2003 server and .net framework.I have installed the office 2007 on my hosting server.It creates the problem and not use the assembly.