Typically the standard port for SLD (most things java really) is 5<IN>00 where <IN> is your instance number. So, following standard practice, your SLD port number would be 55100.
As for the logon issues and forbidden screens, you probably need to add further authorizations to your IDs.
Look for:
SAP_J2EE_ADMIN
SAP_SLD_ADMINISTRATOR
If you want to, you can search for *J2EE*, *ADMIN* and *SLD*.
After you've added those roles to your ID, try logging in again and running the config.