Access Database in Shared Folder

Hi, some data that I want to access from my asp.net application is stored in a shared folder.
I've set the connection string like below:
Dim Connection As New OleDbConnection("Provider=Microsoft.Jet.Oledb.4.0; Data Source=\\myserver\myapp\mydb.mdb; ")
But the apllication fails because it says it does not have permission to access the file. I've tried many different things but what permission am I missing?
Many Thanks