I finally found this thread.
error -36 has nothing to do with permissions. {...}
http://support.apple.com/kb/HT2433?viewlocale=en_US
There I read:
Type -36 error (I/O Errors (bummers)
This file is having difficulty while either reading from the drive or writing to the drive.
The file may have been improperly written data to the drive or the hard drive or disk
may be damaged. This is almost always indicative of a media error (hard error on the
disk). Sometimes (rarely) it is transient.
Solutions: Try copying the file to another drive. Use a disk recovery software, such as
Disk First Aid to examine the disk. You can try rebooting with all extensions off. Once
in a while this will allow you to read the data. The file in question should be restored
from a backup that was stored on a different disk. Regular backups can reduce the
time to recover from this error.
I don't believe the media error/hard error hypothesis! In my case
(
http://discussions.apple.com/message.jspa?messageID=10882048&tstart=0)
"writing to the drive" can't be the problem, because a folder is just
read
to be copied to another Mac's Drop Box.
"Reading from the drive" can't also be the reason, because there is *no problem*
to make a copy of the folder on the same hard drive.
What else could it be...?
Maybe the suggestion given at
http://db.tidbits.com/article/10743 and
http://db.tidbits.com/article/10772 could help (in some cases) but I didn't
try it. I need a simpler solution which I can use every day without cryptic tricks.
I found "Personal Backup" by Intego. I thought that for the purpose to copy
for example the iPhotp Library to another Mac I would have to copy ALL
files (the invisible files too!) and configured "Personal Backup" to perform such
a transfer. Again it didn't work, BUT when I changed the settings to copy
only the
visible files it worked perfectly. So do I really need these invisible files
on another Mac? For example when I want to use the copy of the iPhoto Library
on the other Mac, would it work without the invisible files?