you should at least try sharing out a folder on another system (eg a Windows box), letting LinuxMCE add that as another media source, then dropping one of the media files you have had problems with onto that share. Now you can play the same media, with the same MD using the same GB switch, but completely eliminating the NAS (NIC, file system, drives, samba implementation, etc). This is a quick way of eliminating the problem, as if you have the same problem again, you can say with authority it isn't the NAS. Then you can turn your attention to the MD and networking (MD NIC and switch)....
Very good tip. Thx a lot.
I'll try it as soon as I get back home.
For the moment I wish you all a very good and prosperous 2010.