Help! File transfer via Peer-to-Peer sharing between Vista and XP

I bought a new HP laptop with Vista and am trying to transfer larges files
from my old HP laptop running XP. I setup an ad hoc (computer-to-computer) on
my Vista laptop and installed LLTD on my XP machine so that Vista can see it.
I enable File Sharing on both laptops, configured the firewalls to allow
sharing on both, and put both under the same Workgroup name.

My problem is that my Vista machine sees the XP machine but can't access it.
My XP machine can't see my Vista but knows its there because it passed the
ping test I ran. I went to Windows Media Player (WMP 11) on both laptops and
enabled Media Sharing. My Vista laptop can connect to my XP WMP and play the
music while my XP still can't see my Vista or play the music.

I don't know what else to do and am so frustrated because file sharing
shouldn't be difficult. Any suggestions?(other then using third-party apps).