I found the problem, my UITextView which displaied the link was over lappting the ads although the overlapping was empty, anyways I fixed it and waiting for apple to approve it.
Do you have an idea of how long could a very small update like this take to review?
Just as long as any other submission. You start from the back of the line, like everyone else. Apple doesn't handle small updates any differently, although if they did (and if implemented to avoid abuse), it would be a nice improvement to the review process.