Ignoring the comments, which refer to different distributions, your
/etc/apt/sources.list file suggests that your machine is running the
jessie release of Debian GNU/Linux.
The sources that you see showing errors all refer to squeeze, and I suspect you'll find that those source-entries are all located in individual files located beneath:
The sources refer to
hpacucli, which are tools to configure hardware-RAID cards. If you're running a Bytemark Cloud server, or a legacy virtual machine, you'll not need them at all - so your simplest course of action would be to remove the files which contain those sources list.
Otherwise you'll want to edit "squeeze" to change it to "jessie" in those files.