large files over windows network

Setup:
2 computers (A and B;both running Windows XP/ in the same workgroup/subnet) connected to the same switch (D-Link DGS-1008D);

problem:
2 files on the folder in A shared in the same folder: (without loss of generality) 1 large (~1GB) and 1 small(~30MB) ; identical permissions.
have problems accessing large files through "my network palces" (or network drives); small files goes through no problem.

Steps to arise the problem: if I attempt to copy the large file from A to B using B (as in entering the command/clicking on B), error message comes up (no error comes up when I copy the smaller file). if I attempt to copy either file from A to B using A, no error comes up.

error message: "Access is denied"

I would like to know how to troubleshoot this. Thanks.

Is there anything special about the large file other than it is large (digital rights management, for example)?

XP Home or Pro?

Any passwords set on any accounts? Esp: does one computer have no passwords and the other has passwords?

Is the file in the "Owners" Documents and Settings folder (contains My Documents, etc.)?

Just kind of fishing here. No clear suggestions yet.

Hmmm... little help from that fishing...

From your answer a couple of posts above, am I correct in assuming the problem file is a media file of some sort? What sort? And, where did you get it?

This is a real flyer, but does the computer that can't access the large file have WMP 11 on it?

update: If I create a user and try the same trick, it miraculously works, so now I believe it is some sort of per-user setting (I want to fix this because of some large number of programs that I direct to the currently problematic folder)

the user trick is at the host (2 users charing their folder within Desktop, one got an access problem one does not); the old user was the one created at install (first boot), the new one created at test (recently); the old user owns all the files (I believe)

Glad you solved it.

I'm happy to be of such tremendous help! :?