"error code -50" when transferring files between NAS & drive

[E3RSys]

I'm not really sure where to look at this point so hoping you good folks can help me figure out what the problem is.

I have a Synology box with 1TB Caviar Black in it. The setup is about 6 months old. It's been reliable and I can't believe I've waited so long to get one. I just upgraded to DSM4.0 but this was occurring before I upgraded the other day.

I made the mistake of moving an old iPhoto library onto it. I don't access it often as I use mainly Aperture at this point. As many do when you try to access an iPhoto library on a non-Mac OS formatted drive, it's slow as molasses. I'm just trying to move the file back to my Mac so I can import them into Aperture but ket getting "The operation can’t be completed because an unexpected error occurred (error code -50)."

I thought I'd try to attach a drive directly to the NAS and transfer that way but same message. every setup I've tried gives the same message. I've tried turning off Time Machine as it seemed to have fixed the problem for some in the google searches I did.

So I checked to see if it happens with other files and it does. Any file transfers I try to make gets that error. I checked the file permissions and everything looks ok. I rebooted the NAS & my Mac. I've tried attaching different drives via USB. I've tried connecting directly. Same error code!

Does anyone have any idea what this could be or how to fix w/o me losing everything?