Rsync problem

[Ganbaa]

Dear Sir,

I'm using rsync over ssh between 2 hosts. Sometimes getting following error 
message:

system /usr/local/bin/rsync -av --timeout=0 -e ssh 
user@host:/usr/home/user/backup.tar.gz /usr/home/user/ failed: 3072;

What is it mean? Can you help me?

Best regards

Ganbaa