This looks like a installer issue rather than a mysql-server issue:
(from Dmesg.txt)
[ 2768.320060] frontend[8475]: segfault at 4 ip 7fefbb591237 sp
7fff6c2f84b0 error 4 in libperl.so.5.10.1[7fefbb4ee000+162000]
(from DpkgTerminalLog)
Setting up mysql-server-5.1 (5.1.41-3ubuntu12.9) ...
--
You received this bug notification because you are a member of Ubuntu
Server Team, which is subscribed to mysql-dfsg-5.1 in ubuntu.
https://bugs.launchpad.net/bugs/708537
Title:
package mysql-server-5.1 5.1.41-3ubuntu12.9 failed to install/upgrade:
subprocess installed post-installation
