I recently added a Promise NAS to my network to host a number of large files that had previously been on a PC mapped drive. A number of these files are .iso file. The mapped drive on the PC was accessible from my Mac. When I double-clicked one of the .iso files it mounted it on my Mac desktop and everything worked fine. When I do the same from the NAS, I am getting an error message "the document x.iso can't be opened. The file is too large." Any ideas why this is occuring?