Roles.GetAllRoles error NT AUTHORITY\NETWORK SERVICE

Roles.GetAllRoles() i get

Login failed for
user 'NT AUTHORITY\NETWORK SERVICE'. I am using membership on via SQL
2005. I have run aspnet_regsql.exe and the asp membership tables are
there. I can use the ASP>Configuration manager to view my roles,
where i can add roles successful

here is my config

  <connectionStrings>
 
  <add name="PrintManager" connectionString="Data Source=my;Initial
Catalog=PrintManager;User ID=xx;Password=xx" providerName="System.Data.SqlClient" />
      <add name="SqlRoleManagerConnection"
              connectionString="Data Source=my;
                          Initial Catalog=PrintManager;User ID=xx;Password=xxx;Integrated Security=SSPI;" />
  </connectionStrings&g ...