different user in my IIS

I've created a Virtual Web Site on my own machine. When I run a Web page, it creates a Excel report that puts on the network drive. I someone else is is running it, from their machine but calling page from my machine, it doesn't create any files. How can I go around this?

Post some more information on the problem.

Probably there is a permissions issue.

That was also my thought, but I'm not sure where to change this permissions.
Again about the problem: I host a Web app on my computer. Web app creates a Excel file when you click a button. If anyone else from the network acces this app, they get error message if they try clicking on that button, saying: "Microsoft Excel cannot access the file '\\"ip address"\WhatIf\Reports'. There are several possible reasons: • The file name or path name does not exist. • The file you're trying to open is being used by another program. Close the document in the other program, and try again. • The name of the workbook you're trying to save is the same as the name of another document that is read-only. Try saving the workbook with a different name. "
When I run the same app, I don't get that error message. I have <identity impersonate="true" /> in my web.config file and IIS is set to Windows authentification (I changed this because in the begginign even I couldn't write those files). What else should I change?

It appears you're running IIS6, I'm not familiar with IIS6 permissions. Hopefully someone more familiar with permission settings will hop in.

Actually, it is IIS5.