I haven't had a problem with the auto log-in setting thus far, none of the changes I mentioned should have affected it anyway. Also make sure that you enter the forum via
http://www.nbaliveforums.com rather than just
http://nbaliveforums.com; the log-in problems seem to be fairly common when you don't include "www".
As Donatello mentioned, you need to have cookies enabled in your browser. Additionally, if your cookie security settings are too high your broswer may not allow cookies that allow you to store auto log-in information, such as the ones phpBB forums use.
Some third party security/firewall programs (such as Norton) can also cause problems with the use of such cookies if their settings are too high or if you download software updates, which are necessary but sometimes change settings or add functions that offer additional protection to the point of interfering with email, log-in cookies and sometimes even general browsing.