I am using 2.4.2 on a LAMP installation. New install, not an upgrade. It is only a local site at this point. Every time I would go in and set up preferences, the site would log me (the Admin) off and then when I would try to login again it would say thank you for logging in, but when it redirected back to the home page I was not logged in. This is with no additional modules, just the three standard at install. I went through various trouble shooting options. I would change things one by one, via phpMyAdmin, back to the original default setting. After many tries, I finally figured out that if I use a custom session this issue arises. When I change it back to no custom session, it allows me to login again. Totally reproducible every time on my system. So I don't know if this is a bug or not, but it sure is on my setup. Just thought I'd let you guys know. And thanks for the great software. I really appreciate it.

Probably you must have a setting or creating an additional directory, or specifying rights for it, to have user sessions.
Check the documentation of your LAMP.
(Or try XAMPP)

I've never had this issue with past versions of XOOPS and I have used many of them. I have never had to make any changes to permissions to use custom sessions. In fact, it was not an issue with 2.3.3. It is something unique to the 2.4 version.

What is the version of your LAMP?

I am using PCLinuxOS version 2010, Apache 2.2.14, MySQL 5.1.41 and PHP version 5.3.1.

The difference with the 2.3.3, was that observed on the same server? Eg if you install V2.3.3 to a subdirectory eg 233, can you check that both methods work?

I'll give it a try and let you know.

Ok so here's how it goes. I've installed several versions on my home server and here is the short version.

2.3.2a installs, then goes to blank page when you hit next at step 11 of 11.
2.3.3 gets to page_configsite.php and then goes to a blank page. Will not continue
2.3.3b gets to page_configsite.php and then goes to a blank page. Will not continue
2.4.0 installs fine, then changing to custom session breaks admin login.
2.4.1 installs fine, then changing to custom session breaks admin login.
2.4.2 installs fine, then changing to custom session breaks admin login.

The live site is hosted at Bluehost. It's bpbows.com. Bluehost is set up with

Linux (unknown distro)
Apache version 2.2.14
PHP version 5.2.11
MySQL version 5.0.81-community-log
xoops 2.3.3 w/custom sessions

When I copy a backup from the web host to a local directory and reconfigure the mainfile, all I get is a blank page. Yes I've cleared the caches and checked permissions. Another thing to is that when I turn on debug via phpMyAdmin I get no output from it. This is true with all the versions with blank page syndrome. The backup from Bluehost used to work on my home machine. Apparently a recent update of php or MySQL has broken it for me.

If you have any ideas I'd love to hear them.