You will have to add a line like
Code:
APT::Cache-Limit "50000000";
to a configuration file of the apt program. I would create a new file called /etc/apt/apt.conf.d/11cache-limit with an editor.

The value of 50000000 is a guess. It needs to be greater than 25165824 and I made the experience myself that 50000000 will be sufficient. If you reissue the command
Code:
apt-get update
then you will see that the error has disappeared.