Just added this to the comments on the authors plugins page.
As it took me a couple of hours to figure out which plugin was causing the problems. I thought I would post this here.
In fairness, the plugin author isn't claiming compatibility with 2.5 (at the moment anyway). But, I know that lots of folk are like me, and try them out anyway, to see if they work in the later versions. Many do. So, just to save you the hassle I thought I would point out this issue.
Anyhow, here was the commenmt:
FYI -Anyone thinking about using this plugin. I tried this on two different 2.5 wordpress blogs. And it had the effect in both of stopping the cron commands.
So, if you do decide to test this out, then be aware of that possible conflict.
As soon as I turned this off in plugins the cron started again on both, so I am sure this was the cause.
Shame. Because its a great idea.
Let me know if that problem gets fixed.