crons not working

[NeXuM]

This has been annoying me since years. Crons are not working on my forum (vb 3.6.4) i don't remember if they ever worked but it doesn't since many years.

I have to login in admincp and manually launch the crons jobs if i want my users to be promoted to the correct groups (i have a promotion set to promote users to a different group when they reach 150 posts).
It works fine when i launch them manually from admincp but it doesn't work when i set it to be launched automatically once every X minutes.

I am 100% sure that everything is correctly setup in the ACP crons section.

I have also tried to reset my footer template to default to ensure the function to launch crons is still there, but it doesn't change anything.

Any clue where i should look to fix this bug ?

Another "solution" would be to write my own PHP code to launch the cron jobs and include this code in the footer.
I have tried copying "admincp/cron.php" and just keeping the "runcron" function then including the page inside an hidden iframe to trigger it every time a user visit the forum. But it will only works if the user is a logged-on admin.

[NeXuM]

any help ?

crons not working cause all sort of problems, for example from time to time my users can't login anymore because the session sql table gets full and i have to manually empty it.

[tbworld]

You have all sorts of 404 errors on your site. Including files that cron is trying to reach.
If you can do a little php you can run a backtrace from the call in your footer and log the data. Tracing through that data will tell you if it is being executed, but I don't believe that is your problem.

I would look at a file permission problem or url rewriting problem.