Can't open folder after failed copy

Question

Hello,
I have a WD MyBookLive NAS drive which, up until Mavericks, I had been succesfully using as a Time Machine backup over WiFi. However after Mavericks it became unusable (This is well documented throughout this site and in other places - however there is no fix in sight).
Having given up on Time Machine for backup (and deleting it's backup archives in a failed attempt at troubleshooting) I went about manually copying my files to a share I had created specifically for this purpose on the NAS drive.
I did a test of about 5 Gb worth of files and all went OK, copying in about 5 minutes.
I then started to copy the rest of my data - about 750 Gb in all, mostly raw video and iMovie files. The copy began and proceeded as expected so I left it alone, However when I looked at it a few hours later it said that a copy had failed because the file "clip-135-02-05 05;27;15.dv" couldn't be read or written, with no option to either try again or skip over the offending file - it simply stopped the copy dead... Grrrr
When I checked the destination folder (after having to re-log in to it) with a Get Info it was 134Gb - so a lot of progress had been made in the copy.
HOWEVER, although I could do a "Get Info" on the destination folder, its icon is greyed out and I cannot open it. Worse yet I cannot delete it. When I tried to do so it deleted about 2/3rds of the content but stopped saying "The operation can’t be completed because the item “clip-135-02-05 05;27;15.dv” is in use."
I tried using "GraveYard" to delete it but it couldn't do it.
I'm now left with a 45Gb greyed out folder that I cannot open or delete...
Any Ideas??
Also, when I searched for "clip-135-02-05 05;27;15.dv" in the source folder, it came back with about 12 files - all seemingly legit, but in different folders - so I've no easy way of knowing which one of these may be the problem file (maybe none of them are, maybe the WiFi failed at a critical point while copying that file and corrupted the destination).
Either way it seems odd that a failure of ONE file during a copy could cause so much trouble...
Help!

Answer 1

Thanks Pierre-Yves
Update:
I was running 10.9.2 - in fact the reason I ended up with this manual copy problem was because I was hoping that 10.9.2 may have fixed the Time Machine problem I mentioned above, but it didn't!
Continuing from where I left off after the failure above...
I thought I'd skip WiFi and use a direct ethernet cable to my router for a more reliable connection. I hooked it up, disabled WiFi and began the copy again from the start. (Copy speed was pretty much the same as with WiFi - I guess this is as fast as my NAS can handle things). The time estimation got to 17 hrs so I left it overnight. The next day it was still going with no apparent problems.
It got to about 620Gb out of the roughly 750Gb BUT then stopped again. This time the error was different:
"The operation can’t be completed because you don’t have permission to access some of the items."
...and again, frustratingly, no other option but to click "OK". Further, it gave no indication of the problematic file.
However, at least this time I could open and examine the contents of the destination folder to see what was and wasn't copied. By doing a few "Get Info"s on the various folders and comparing sizes and file counts I was eventually able to identify which files and folders didn't make it. (Oddly it was a selection from roughly the middle of the original folder list - sorted alphabetically, I thought it would have been at the end).
I started to copy the missing items, fully expecting to come across a permissions error at some point. However I didn't and was able to complete my "backup". When I compared "Get Info"s on the source and destination folders they showed the same number of items and roughly the same no of bytes - Good enough for me.
So, for now, my immeadiate problem of not being able to make a backup has gone away.
Nonetheless, my experience with this (and the well documented Time Machine problems) leaves me doubting OSx reliability (how can there be problems with permissions during one copy attempt but not the next?) and user friendliness. I'm not a Windows fan by any stretch, but at least when Windows has a problem copying it tells you which file it had the problem with and offers you to skip over it and continue with the copy. With OSx, it's all or nothing with no remedies and often no meaningful fault indication... Very frustrating...
One last thing: I had mentioned in my first post that I had been left with a Greyed out image of a 45Gb folder that wouldn't delete. I tried again today and, although it was still grey, it did actually delete - so at least that somehow fixed itself...
Thanks for your input.
I await the next OS update to see if things improve...