script in background with scheduling

[da_ver]

With ajax I can run a script in the background and I dont have to wait for een answer. But I have another problem.
Here is an example where I explain the problem.

Somebody will register on the website and after 2 hours I want to check if the person has already confirmed his registration. If not send a notification mail.
so if the person register there must be a script in the back that sleeps for 2 hour and then checks.(but here is the problem time out)

But on the hosting where the site is (and they dont want to change from hosting)
are some limitations: safe mode is off and open basedir is on

The following functions are disabled:disk_total_space, diskfreespace, exec, system, popen, proc_open, proc_nice, shell_exec, passthru, dl, set_time_limit en de 5e parameter in mail().
And there is no cron possibility

Can anybody help me to make this work?

[dagon]

move host, really using a crippled host is not worth the hassle, and moving host is not hard

the only alternative is to use visitors as a trigger. that is to check the registration db, for emails to send on every hit of the index.php, depending on site popularity, you may chose another page to be the trigger.