Yes Vanessa, that´s right. The verb "see" in the gerund form (seeing) can´t be used to express actions that are happening righ now
(present continuous - I am doing
To say "você está vendo aquele homem lá?" you would say/ask in English "Do you see that man over there?"
Normally, the same happens with the so-called sense verbs - see, hear, smell, taste.
Example (from the transcript of Good Will Hunting):
HYPNOTIST -Okay...you are in your bed, Will. Now...how old are you?
WILL - Seven.
HYPNOTIST - What do you see?
WILL - Someone's in my room.
HYPNOTIST - What is it?
WILL - It's like...uh...it's a figure. It's uh..hoverin' over me.http://www.moviescriptsandscreenplays.c ... trans.html
The same happens with the verb "mean", you ask "What do you mean?" (O que você está querendo dizer com isso
?) and not "What are you meaning?"
or What do you meaning?