后来才想起来，原来DCOM又忘记配置了~
然后在网上查，又找到了另一种方法，就是在web.config中设置一个节点，也可以同样达到这个效果，不需要设置DCOM权限，两种方法各有利弊吧
U need to impersonate the aspnet account when trying to access office applications which requires administrator privileges. By default the asp.net application runs with the privileges of the account : machinename\aspnet
and, this account does not have administrator privileges by default.
u can do 3 things to use an administrator account for your asp.net applications:
1. Add the machinename\aspnet account to the Administrators group by using the computer management console.
2. Use an account which has administrator privileges on the web server machine: to do this, open ur web.config file, just below the authentication tag write this line:
<identity impersonate="true" userName="machinename\administrator" password="admin password" />this is called impesonating asp.net to use a fixed account.
3. Open ur web.config file, just below the authentication tag write this line:
<identity impersonate="true" />and, logon with an administrator account on this machine before running the asp.net application. This method is called impersonating asp.net to use the logged on account.
FYI: http://support.microsoft.com/default.aspx?scid=kb;en-us;257757