I get the "your content couldn't be saved" message EVERY time I'm on these forums and EVERY time I try to post and it comes up all the time I'm writing. It's come up about 10 times just writing this!
We're aware. Try two things that might help.
1 Ignore the warning. I never click it and just keep typing.
2 go to activision.com and log in there also. That way you are logged into both callofduty.com and activision.com