[support] Update.php error with Drupal 6

Hello,

I'm running a new installation of Drupal 6.2, and I have a problem running update.php. Going to example.com/update.php, the page looks fine except for a red box at the top that says this:

warning: Cannot modify header information - headers already sent by (output started at /var/clients/client0/web2/web/sites/all/modules/devel/devel.module:1538) in /var/clients/client0/web2/web/includes/common.inc on line 141.

So, I click Continue anyway, which takes me to the next page. This has the same error at the top. I click Update, and this gives me a blank page.

Any ideas what may be going wrong?

- jody