We need the full log to access what the error is. Please paste a server log in to pastebin.com and link to it here. You might also want to check the configs and mods on one of the clients in an SSP world to see if it still stops. If it still crashes we would need a console log in that instance. It is easy to get the console log just click the 'Paste my log to pastebin.com' when it stops at loading the extra bees. Look
here for more info about the logs.