Ok we found that the solution for accessing the network share is by impersonation, more can be found at http://abibaby.blogspot.com/2002_11_01_abibaby_archive.html
When i give user name, password in impersonate tag it does not work.
This happens as ASPNET account by default is not eligible to impersonate in .NET. First we need to address this issue. We need to Go Local Security Settings–>Local Policies–> User rights Assignments –> Add ASPNET user to “Act as part of the operating system” user list (second option).