[Evolution] Corrupted backup TAR archives

[portsample <temp1 blepsias net>]

Recently, I've noticed that my Evolution backups (Evo v.3.2.3, openSuse
12.1) have been varying in sizes, (6.9GB-8.3GB) and the produced
archives have been reported as corrupt when I've tried to expand them
into a new account.

I have also tried
importing /home/user/.local/share/evolution/mail/local_mbox/Inbox into
Evolution directly and was partially successful with the Inbox contents
from 2003-January 2012 copying, but January 2012 to current not copying.
I've also tried copying my entire home directory to a different machine
running Evolution 3.4.4 with no success regarding historic email
contents.

Curiously, the installation that I'm trying to pull the backups from can
read and search the 2003 - 2013 emails with no problem. 

I'd really like to do a complete backup of my 2003-2013 emails for
migration to a new machine at some point. Is there a better low level
method to do a backup and restore? Should everything in the inbox be
restored when I
import /home/user/.local/share/evolution/mail/local_mbox/Inbox? 

Thanks for clarification and enlightenment regarding this issue.