Irssi+Cifs Problem

Hi, I have this problem with irssi. Irssi run in a linux box. I set as 
dcc download path a cifs mounted path. The user that run irssi have rwx 
permission on that folder. But when i try to download a pack, irssi say me
"Operation not permitted". I try to change download path, and it work. 
But my intent is to use  a windows shared folder as download path. Can 
some one help me? Thanks a lot.