A da probas da i u Share Permissions i u NTFS security permissions stavis everyone - full control (probe radi).
Ne verujem da je problem u lokalnim polisama (obicno kaze nesto tipa: Local Policy Does Not Allow ...), ali probaj sledece:
start>run>gpedit.msc>Computer Settings>Windows Settings>Security Settings>Local Policies>User Rights Assignment, pa tu vidi neka podesavanja (Access this computer from network, Create permanet shared objects,...)
Ovo preporucujem mnogima: pokreni na problematicnom kompu Network Setup Wizard...
Mali je glup, al' se uporno trudi!