Remote to Vista Business from XP Pro Error

After looking at all of the postings, I still can't find an answer so here is
the problem.

I have a laptop running Vista Business, with remote turned on. I'm trying to
connect to the notebook from a desktop running XP pro. I do connect to the
Laptop and get the "sign on screen" but after I sign on it will give me a
"Timed Out....." warning after awhile.
Now the laptop is running on wireless and we are doing this on our in house
network and not thru the internet. So what could be the problem on the Vista
Machine?

Could it be that the desktop doesn't have enough RAM in it (512MB ram) to
run the remote Vista so in return I get the time out warning ?

Thank for any help!