What does this error mean?

[Byzantine Emperor]

While I was modding BI, I decided to test what I had done, but I get this error. Battles run fine, but the campaign crashes with this error message. I have not modded the campaign:

https://img156.imageshack.us/img156/6748/errorxs4.jpg

I have never seen this before. What does it mean?

[Dol Guldur]

Check you unit textures - that they are named and saved and coded correctly.

[Byzantine Emperor]

How can it be a unit? The battles work fine.

[Dol Guldur]

That error message - from my experience - crops up when cas and texture files have been modded. Unless you've modded other non-unit textures?

Try enabling the slave faction for custom battles and load the units up and see what happens.

[reahad]

I got that error too when I tried to add an Alexander unit to vanilla.