Access to shared folder with an asp.net application using forms authentication

Hi,

We have an ASP.Net application which uses forms authentication. I am trying to access a shared folder using the application and facing access denied errors.

Can you help me understand how to setup correct permissions.

IIS Server and the Server which has the shared folder are not part of a windows domain. Application pool is running with NETWORK SERVICE account and it has full control access on the shared folder. 

Thanks.