WSS 3.0 Sharepoints alerts are not working.

Hi,

In our company we have problems with the sharepoints alerts (SP 2007 on windows 2003). No one receives the email alerts.

Other mail functionality works correctly.

When a user installs an alert he receives an email "You have successfully created an alert for ...".

* It was a new installation so it isn't an upgrade problem.
* The mail settings in the central administration are OK

* Timer job status:

Immediate Alerts

oppnsps01

Succeeded

100%

1/3/2008 10:35 AM

* In the logs i don't find errors
* I tried the following commands: NOK

stsadm.exe -o setproperty -url http://oppnsps01/sites/library -pn alerts-enabled -pv true
stsadm.exe -o setproperty -url http://oppnsps01/sites/library -pn job-immediate-alerts -pv "every 5 minutes"

* I've requested and installed the latest  hotfix package: NOK
* It's not a permission issue -> i have the same problem and have all rights

Can someone help?

Thanks.

Gr,

Frederik