Impersonation failing for a user.

Hi
I am using impersonation in asp.net web application because I need to write on a network drive. It works fine if I use a set of credentials on shareA path, but imersonation fails for another credentials set. The users are in different domains and netwrok drives to access are different too.

For the second set credential, it is failing to load the webpage itself. The error it gives is

Line 67:             <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
Line 68:         </httpModules>
Line 69:         <identity impersonate="true" userName="i\user" password="xxxxxxxx"/>
Line 70:     </system.web>
Line 71:     <system.code ...