I am also using .net 3.5 (working with code I wrote 10 years ago). Interestingly I can query the aspnetDB database with VBS.net code.
Please try the following default settings:
<roleManager enabled="true">
<providers>
<clear />
<add connectionStringName="ConnectionStringMain"
applicationName="/"
name="AspNetSqlRoleProvider"
type="System.Web.Security.SqlRoleProvider" />
</providers>
</roleManager>
Note that "ConnectionStringMain" must be the connection string to your aspnetDB database.