I am experiencing crashes outside in my current game and don't know what is causing it, these are the last few lines from my papyrus log:

stack:
[ (00108206)].critterSpawn01.OnLoad() - "" Line ?
[07/30/2013 - 10:49:58PM] Error: Attempting to manipulate variable "recursions" was not successfully looked up
stack:
[ (00108206)].critterSpawn01.OnLoad() - "" Line ?
[07/30/2013 - 10:49:59PM] Error: Argument variable "bLooping" was not successfully looked up
stack:
[ (00108202)].critterSpawn01.OnLoad() - "" Line ?
[07/30/2013 - 10:49:59PM] Error: Argument variable "bPrintDebug" was not successfully looked up
stack:
[ (00108202)].critterSpawn01.OnLoad() - "" Line ?
[07/30/2013 - 10:49:59PM] Error: Argument variable "recursions" was not successfully looked up
stack:
[ (00108202)].critterSpawn01.OnLoad() - "" Line ?
[07/30/2013 - 10:49:59PM] Error: Attempting to manipulate variable "recursions" was not successfully looked up
stack:
[ (00108202)].critterSpawn01.OnLoad() - "" Line ?

What does critterspawn mean? is it from a mod? I fear my save game may have some unused scripts in it as its around 14mb big with 92hours recorded and I have swapped a lot of mods around with it. Is there anything I can do?

Critterspawn is a script. It control critter spawners, that are responsible for putting critters in the world.

OnLoad() is a function/event internal to the script, and the various variables mentioned are used in the original version of the script. You apparently have a mismatch between the current version of the script and either your save or some other script it needs to interface with. That is purely a mod issue, and although issues like that may be cleared with skill and patience, my guess is that in practice your goose is cooked due to reckless modding, especially if you have loose script files in your Data folder.

Some house mods may attempt to rewrite that script, because the vanilla version does not work properly in interior cells, and I am aware of at least one house mod, that drops it own ill-thought version of that script into the folder as a loose file, and it is nothing but trouble.

It is time to unload mods and dig into earlier saves, that you have as back-up copies from before installing each new mod.

Right i see, this save/char was my very first from the game launch day so you can imagine everything that has changed since then. I was hoping to go further with this char but it seems his time is up.

Would it make any difference if i uninstalled each mod and then reinstalled checking if the error is still present?

Edit, what house mod are you referring to? As i have quite a few.

It would probably make things worse, as Skyrim does not really support uninstalling mods. Especially scripts can be permanently baked into your save, and there is no way to remove their effects. Some tools may claim to do that, but in reality they just cause additional damage.

Installing a mod in Skyrim is like getting married used to be: you are committed for the duration of your character.

Before you commit yourself to playing with a new mod, you should always first test it for a while, and have a backup save from before you installed it, so you have something to go back to if things don't go well.

Edit: I don't actually remember the precise name of the house mod in question, I just once noticed it when somebody complained about critter issues with it, so I had a look at the script that came with it. I don't want to try to remember it either, as I wish to give the mod maker the benefit of doubt; maybe it is fixed, maybe it is not. It is just good to be aware, that this is a potential issue with house mods in general, if they feature indoor critters.

Thanks for the advice, im going to be more careful on my next char and like you say, stick to one load order.

I will retire my char with some excuse and start fresh. Trouble is i want to use most of the mods i currently have but dont know if they are stable all together, guess the only way to tell is add one by one and see if i get any ctd's?

Btw am i right in thinking its safe to uninstall mods which dont have any scripts included?

Right. Install new mods in several steps, preferably one by one.

I think scripts are clearly the most troublesome, but I can't really give a 100% certain answer to your question. However, texture mods are usually very safe to install and uninstall.