pb with rights on mapped drives

Hello,I just added a Vista Business workstation on a network.This one is correctly added to my domain. no problem.BUT: I create mapped drives with a batch using net use. drives creation is ok, read access is ok... but not write access!! those shares comes from a Windows 2003 server R2 (domain controller)...Obviously, rights are set to full control both in authorization and security panels, and set to full control for everybody (first it was for user groups but thought it doesn't work, it set it for everybody for test purpose)> my drives are ok on Windows XP, Windows 2000 workstations... and I'm using the same batch script... they CAN modify files in mapped drives...it looks like as if Vista decided his own to block write permissions!! even logged as domain administrator on this vista workstation , I cannot succeed in modifying files in my mapped drives...all the finest of all: logged as a domain administrator, I tried to explore my server using \\server\c$ what a domain administrator has right to do so.... Well, I gained access, no problem... I couldn't modify any file!!!!few days I'm on this... I can't find any solution or explanation either...