I can't write any message on the wall of my friends

Since today I can’t write any message on the wall of my friends - why? Maybe it’s a bug?
Before, by openning the profile of my friends, I saw my icon and a field near this icon where I could write any message. But today I see only the word ‘wall’ but no space to make a message.
Do you have a similar problem?

Hi Evgueny,
Strange, I can post on users walls without any problem. Can you give it another try?

Thanks, Zoran!
It works now, it didn’t work only one day.