NAS Data Corruption?

I recently purchased a Thecus N5200Pro and loaded it up with 5 1.5TB drives in RAID 6. The intent was to load all my pictures and music on the drive, but when I copied everything over I noticed several of the pictures were corrupted. I then recopied the picture files and did a full compare and found more than 10% of the files were corrupted (3,600 of 32,000 files copied did not match the original per DLSuperCBF compare). That seems absurdly high. Anyone have any suggestions on how to go about finding the problem? I thought about repeating the experiment using xcopy /v instead of windows explorer just to see if that improved matters (though that's hardly the long term answer). Pinging for about 15 minutes dropped 2 packets (1%), so abundant network noise doesn't seem like a likely culprit (though I'm not ready to completely dismiss a possible network error. I just switched over to a Netgear WNDR3700 and while it seems solid, it's too new to be entirely confident. A bad drive in the NAS is possible, but I've received no errors at all. I have a complete file system check running now, though it hasn't found anything yet. Any other suggestions? Has anyone ever seen anything similar? I'm looking for any suggestions I can get - I expected this to just work and never even imagined having to work through something like this. Thanks!

Yep. I do realize RAID is no substitute for backups. That said, I need a more reliable primary storage device. Good idea on contacting Thecus; I opened a ticket with them. I'd still love to get the thoughts on anyone here who might have experienced anything similar. Thanks.

After a little more research I learned that data corruption issues on a NAS most often come from a bad network adapter. Some sleuthing using different machines and ports finally proved my problem originated with the NIC on my PC MB. I dropped in a new gigabit adapter and everything is now working perfectly.