If it was a random server restart (A crash) chances are the script was unable to properly save the data properly into the correct locations. This is most likely the reason. If it was a planned restart (you got a notice), you may have not have chosen to save your current info.
Do you see your monster now? Have you tried re-logging/ going to the trucks re-spawn location?
Guests: 145
Hidden: 0
Users: 0