Hi Kerim;

In the past, I have encountered this problem when the PHP sessions directory was not accessible.

Check the php.ini file (session.save_path parameter) for the directory setting or php error log file to see what directory is not writable. Create this directory, making sure it is writable by the web server process.

Maurice Joseph SpikeSource, Inc. developer.spikesource.com

Kerim Friedman wrote:

If your hosting provider is using a server farm with multiple hosts, the default PHP session configuration may be storing data on a local drive which breaks things.

Try checking the directions for running on Sourceforge, which has a similar issue: http://meta.wikimedia.org/wiki/Sourceforge#Sessions

Just making a directory isn't enough; you'll have to configure it, as described there.

-- brion vibber (brion @ pobox.com)