You forget to not send… directories and disks…
Your remote sftp create directories when are not presents?
:local filelist ""
/file
:foreach file in=[find where type!=disk and type!=directory] do={
/tool fetch url=("sftp://XXXXXXX/$file") upload=yes user=backupuser password=ashahahha src-path=$file src-address=92.x.x.x
}
For true backup you can adapt this, is by mail, but you can modify it to use fetch:
http://forum.mikrotik.com/t/router-crashes-are-wiping-the-config/149189/7