Privileges/permissions from Win to Mac

Hi.

I must apologize because I'm sure this matter has already being discussed but I've searched a lot and didn't have the correct answer (regadless also the fact that I'n not English mothertongue and suffering from a sort of "learning" dislexia).

I need to send file and folders form a couple od PCs (1 has WinXP-SP3 and the other has Win 8.1) and when the files are on the Mac (with Leopard OS) , the priviliges do not permit to move files or folder without the system's password request.

I've also created a user on the Mac with the name of the one on WinXP and gave Administrator privileges but nothing changes.

Users in Sharing Prefs. are also set to Read & Write. I've also simulated this at home from a Win7 Pro to my 10.10.3 with no success.

I have no more ideas... therefore any help (also links to other posts in this forum) is appreciated.

Thanks and sorry again for boring you.

Simon