Define a connection profile in web.config:
<GeoUserManagementConnection>
<Profile>Access</Profile>
<Host>C:\Programme\SynerGIS\UserManagementAdminDB\UserManagement_v51.mdb</Host>
<Port>0</Port>
<DatabaseType>MSAccess</DatabaseType>
<DatabaseName></DatabaseName>
<Username></Username>
<Password>Te06De40e4o=</Password>
</GeoUserManagementConnection>