Weights not staying put

[devilman13]

Hi Guys

I'm painting weights on my character with everything on hold but to one thing I'm painting. I'm painting back3 hold off and turn back4 on hold. Now I change it so the hold is on back3 and off back4 and start painting. I finish and turn back3 hold off to check it and the weights poped back to the way it was, like I did nothing at all. I can go work on a different part and the back3 keeps popping back to the original way it was with no paint? Plus I'm getting this error massage sometimes on different areas

Warning: Specified weight could not be set due to locked influences.

What is this and why does it keep coming up?

Somebody said to In your attribute editor, select your skinCluster node and uncheck maintain max influences.

But it didn't work

Thanks Guys