Changed while reading Joomla 2.5

Hi,

i've upgraded from ispcp to i-mscp. Now i get error mails every night at about 2 o'clock.

This is the error message:

Quote

Dear admin,
I'm an automatic email sent by your SERVERNAME (IP) server.
A critical error just was encountered while executing function main::backup in
/var/www/imscp/engine/backup/imscp-backup-all.
Error encountered was:
=====================================================================
main::backup:
/bin/tar: ./htdocs/cache/page: Datei hat sich beim Lesen geändert. (Transplation: changed while reading.)
=====================================================================

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I've no idea why. I'm also the webmaster of this webpage and there is no FTP connection or something else.
There is an Joomla 2.5 CMS running on this side.

I hope you guys can help me.

Thanks!

Quote from gOOvER

You can ignore them, because it's no error.

But there is only one backup in /backup.
There should be the database and webspace backup.