Problem with custom php codes and pages links

Hi everyone, I was able to create a custom members registration php code using an external database for that, and I am using the twentyeleven theme for a test, the code includes a register page, a login page, logout, and when a member logs in, I have a member profile page, where there is the profile and the member is able to edit the profile, things work well with the external database, and I use the include php plugin, my problem is, for example, I have the login page (custom page), with the login code included with the plugin, now, when the person logs in it has to go to the member profile page (custom page), and I have the member_profile script included with the plugin, but for the login script to get the members info and id the url is “member_profile.php?id=$id”, I cannot put that in the permalink, and it does not work with the script included in the page, so what happens is I can’t connect the two pages’ scripts for the login, any ideas on how to do this? thanks!