Ok thanks a lot for helping me out on this. That works!
I am trying to understand these codes. I know something goes wrong with getting/using the user_id. Please allow me to ask you some questions:
-This is outside the loop, so the user_id needs to be specified right?
-The user_id is used in the $current_author variable, in
echo get_the_author_meta( 'facebook', $current_author ); right?
-The user_id is obtained in the code
$current_author = get_query_var('author'); right?
-Now, how should i find out that getting the user_id is accomplished through
$current_author = get_query_var('author');? I have read the codex, but can't find/see this solution as such. Am I missing something?