It means there is a mod that is crashing your startup.... It will load the intro screens and title screens but won't let you load the actual game right? I had that problem too, it means that one of your mods that has been installed since the last time you played is messed up. It sucks but you'll have to go through them one by one to figure out which one it is....and then uninstall it or see if you missed a fix somewhere or if the files are in the right places,or if it conflicts with another mod (Load order mods don't pick up ALL conflicts)
by 
Calendar
