I'm sorry if this sounds obvious - but have you tried to launch the game without any mods in at all? If there are no problems without any mods in, then that indicates a mod is the problem. Then if that is the case you will need to do a 50/50 process. This means removing half the mods - if there is no problem then you know the problem is with one of the mods you removed, or if there is a problem it's due to a mod still in the game. Then keep whittling away with what mods you include/exclude until you end up with the one mod that causes the problem - it's time consuming, but works. Don't save your game while doing any of this to avoid saving progress without your mods in - or if you feel compelled to save, do a save as. Sorry if you've tried all this, but it doesn't sound like you have isolated if it's a mod or not in your message.
