I know, I tried that and it works.

What I meant was that at the index it only looks at this day. On the portal it shows the whole week. I thought maybe someone has used an invalid date, for a day later this week. For example: 18 jan 2012, which is in the future and it would calculate an age of -1 ...

It works on the forumindex, no error.

I think on the forumindex only users with their birthday today are shown, while on the portal users who have their birthday this week are shown. So I might get an error on the index later this week (hopefully not ofcourse).

It's the same. Is that good or bad?

Your Portal Version: 1.0.6
Your phpBB Type: Standard phpBB3
MODs installed: Yes
Your knowledge: Basic Knowledge
Boardlink: http://www.seriejunkies.nl

PHP Version: 3.0.7-PL1

What have you done before the problem was there?
Nothing related to the portal and/or birthdayblock phpcode ...