MOSS Timer Jobs May Run Late or Not At All
The MOSS OWSTimer.exe process controls and executes all timer definition jobs for SharePoint. The challenge encountered and detailed by the following KB Article indicates that a bug may cause the OWSTimer.exe to be one hour behind.
In actuality, I have seen instances where depending on the time zone there is a two hour difference, or it works perfectly if your PC is set to Pacific Standard Time. My unscientific gut reaction is that perhaps the OWSTimer.exe or code it executes believes that the time zone is always PST.
The workaround as outlined by the article is to determine the difference on your server and adjust the timer job definitions accordingly to accommodate for the time difference phenomenon in the product.