Access to the path"xxxxxxxxxxxxxxxxxxxxxx" is denied

Hi everyone, 

I created XMl files in App_data folder and performing adding user and removing user for that xml files. This appplication is working fine in my desktop like i can add user and remove user from xml file. To day i send that code for testing in development server. But i dont know why im getting error like Access to the path"D:\export\appl\website\emrdevl\run\App_Data\admin_users.xml" is denied. I gave full permissions toasp.net processor but still getting error.Can any one help me out in this issue. I am attaching the code and picture please look at it. if anybody knows answer for this question please let me know.
 'remove user from Admin table

Protected Sub AdminRemoveUser_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Adm ...