Have a look in the work directory. Does the dispatcher even attempt to start the work processes? Files with naming convention dev_w* should exist if it does. Do these files contain any error messages? The error messages are normally very descriptive. Common startup problems are related to SAP being unable to connect to the database or being unable to allocate a sufficient amount of memory. Typos in the instance profiles are also often the reason of start-up failures.
This was first published in February 2007