Access denied if my asp.net app try to read files on network

Question

I have installed my asp.net application on a server. If i go to this server and run the app with IIS and browser, it opens the application and i can upload or read a files to/from another computer on the network.

But if i run the application from another machine on the network and try to upload or read some files on that network it is saying access is denied.

I try to add security permissions for IISUSERS, NETWORK SERVICE, NETWORK on the folder where the app is installed but nothing helps. Also i create impersonate account and add it to web.config. and also in security tab of the folder.

Nothing of this helps. Does anybody else have this kind of problem?