An invalid character was found in text content

I have a big problem with cfs3.
Each time I want to save a campain, CSF3 stops and this message appears: An invalid character was found in text content :'(
I found out that the invalid characters were in two files:
preload.xml
shaders.xml
I just don't know how to fix it, anybody could help???
Each time I want to save a campain, CSF3 stops and this message appears: An invalid character was found in text content :'(
I found out that the invalid characters were in two files:
preload.xml
shaders.xml
I just don't know how to fix it, anybody could help???