For Mepis 11? Because it can't be installed on a Debian 6 (Squeeze) base; please don't blame MEPIS when you find that you can't install new software on an older OS that is incompatible with it!Why doesn't the community repository's Main section have a version of LO that is in the 4 series (at least 4.0)?
You can install Mepis 12 and run LO 4.x on it, though it is no longer being actively develooped, and I used it as my production OS until I switched over to MX-14 a few months ago. Ubuntu 14.04, like MEPIS 12 and MX-14-2, is based on Debian 7 (Wheezy) so LO 4.x can be backported and installed on it.