Unsupported operand types in html/drupal/includes/common.inc

I have the same error. Created a new user with 'authenticated user' permissions and I get:
Fatal error: Unsupported operand types in /srv/www/htdocs/includes/common.inc on line 1369

When I try to log in with this username.

What that means is one of your contrib (not core) modules is not correctly using url() (or l()), which changed from D5 to D6 to use an array instead of a list of parameters. You'll need to try disabling a group of contrib modules at a time to narrow down which one is the problem.

thx Dave for advice. In my case it was comment_notify_module. I had to uninstall it.

If it was http://drupal.org/project/comment_notify, greggles is really good about responding to issues in the module's issue queue. It actually looks like it was fixed #324992: node author notification was not ported properly. Make sure you're using the most recent 6.x-1.x version. It's the version I'm using on my live sites and it works just fine.

The users inside organic group got this message during sending comment. It was definitely comment_notify. And of cause i am using most recent 6.x-1.x version.

I am ugraded from d5

I get this when running cron from a not-logged-in browser ; disabling Community Tags (6.x-1.x-beta) "solved" it

I've been getting this error intermittently when cron.php runs in a cron job. I have Drupal 6.8, and don't have the comment_notify module.

It's definitely the "Boost"-Module which causes this error after clicking on "register" button. Thanks for the tip "akwala" :)

Do you guys have fix this problem? I have uninstalled boost also after installing it and found the error.

I have same bug. When I tried to add new node of some type and unmark "publish" so the things I had written would be saved. I don't know of any Boost module. I don;t have it. I'm using Performance, but my guess it's different. I have no idea what could cause such a mistake. I have added only Imagenodes recently. Athlought after uninstallation of this bug still resists. I was able for adding unpublished node and no problem appeared until today. I've changed only onething, which is some Types. Do you know what could cause such a bug?

spookypld, please check out the new troubleshooting FAQ page about this error that explains how to debug this problem and find the offending contrib module. I'm marking this as 'won't fix' since Drupal core does not babysit broken code. It is up to the module maintainers to write and test their code.