Copy single file using robocopy

I'm writing on a batch file to copy a certain file to a samba-share.

I've already read robocopy transfer file and not folder and thought I would be good using

robocopy "E:\Some\Path\with spaces" "\\sambaServer\some\path\with spaces" "myFile.rar" /z /MIR

But I keep seeing

Source: E:\Some\Path\with spaces\
Destination: \\sambaServer\Some\path\with spaces" myFile.rar \Z \MIR\

Files: *.*

And ofcourse I get an error

ERROR 123 (0x0000007B) Accessing Destination folder \\sambaServer\Some\path\with spaces" myFile.rar \Z \MIR\ The syntax for file name, folder name or the volume label is incorrect.

So apparently robocopy takes the whole second part - the destination folder, the file and the parameters - together as the destination folder.

Why is this not working? What am I doing wrong?

It worked when I copy the whole folder instead using

robocopy "E:\Some\Path\with spaces" "\\sambaServer\some\path\with spaces" /z /MIR

Huh, I'm not sure, but it looks like it can be permissions issue, see here http://blogs.technet.com/filecab/archive/2008/07/31/robocopy-mir-switch-mirroring-file-permissions.aspx

For me robocopy works fine:

robocopy "D:\test" "\share-name\folder-name\test test" "11.rar" /z /MIR