using Domino in .Net1.1 - error "Could not open the ID file"

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I have a winodws service which sends email using Domino. The service is
installed using System Account but it is not able to send emails and gives
following error -

Error Message: Notes error: Could not open the ID file
Error Source: NotesSession
Error Stack: at Domino.NotesSes sionClass.Initi alize(String pPassword)
at
JPMorganChase.P atrol.Notificat ion.Library.Lot usNotes.Email.. ctor(String
NotesDatabase, String NotesPassword)
at JPMorganChase.P atrol.Services. Notifications.S ender..ctor(Str ing mode)

I tried different ID files to authenticate lotus notes session but unable to
make it work.

Any help is appreciated.
Thanks