Does anyone have the full installer for FreePBX 2.9 distro or have any idea how I can import a backup from FreePBX 2.9 into 2.11.
A physical PBX system went down at a client site and the 2.9 net installer disk I have for it does not work anymore (Net installer is no longer available).
Well not from a backup. You could try to load up just freepbx 2.9 on a random system and attempt to work with upgrading that and then move that backup to the new system. Sorry we don’t have better answers for you. it’s not a perfect system 
In the spirit of open source, and based on my reading and understanding the process and with reference to . . .
http://wiki.freepbx.org/display/HTGS/Installing+FreePBX+on+Centos+6.3
I offer a script that should take the latest FreePBX distro and regress to your defined VER_FREEPBX :-
#-----begin---------------
#!/bin/bash
cd /usr/src/freepbx
./install_amp --uninstall
cd …
rm -rf freepbx
rm -rf /var/lib/mysql/asterisk*
export VER_FREEPBX=2.9
svn co http://www.freepbx.org/v2/svn/freepbx/branches/${VER_FREEPBX} freepbx
cd freepbx
mysqladmin -u root create asterisk
mysqladmin -u root create asteriskcdrdb
mysql -u root asterisk < SQL/newinstall.sql
mysql -u root asteriskcdrdb < SQL/cdr_mysql_table.sql
ASTERISK_DB_PW=amp109
mysql -u root -e "GRANT ALL PRIVILEGES ON asterisk.* TO asteriskuser@localhost IDENTIFIED BY ‘${ASTERISK_DB_PW}’;"
mysql -u root -e "GRANT ALL PRIVILEGES ON asteriskcdrdb.* TO asteriskuser@localhost IDENTIFIED BY ‘${ASTERISK_DB_PW}’;"
mysql -u root -e “flush privileges;”
./start_asterisk start
./install_amp
amportal a ma installall
amportal a reload
#----------- end --------------
You should be able to ignore the bitches and whines as the script progresses (or modify php.ini to suit the old script)
season to taste 
Restore your backup to this guy, then follow the “module admin/upgrade” steps to the latest. You will not have any of the neewer “commercial but free” encumbrances however
The Script worked it downgraded the 2.11 distro like a charm. Thank you!!
An issue I started to have was
“[error] [client xxx.xxx.xxx.xxx] PHP Fatal error: Incompatible file format: The encoded file has format major ID 3, whereas the Loader expects 4 in /var/www/html/admin/modules/sysadmin/functions.inc/general.php on line 0”
When I deleted the sysadmin module folder it allowed me to log into the GUI and start the upgrade process.
I had to make some file permission fixes here and there but I now have all my settings on a 2.11 box.
Again thank you of the script and advice.
Excellent,
What file permission problems did you run into, I would be curious to know
Everything inside the /var/www/html/ had some funky user name as its owner and group.
once I changed everything back, ran amportal chown, amportel restart the issues where resolved.
Thanks, probably the tar format of the backup. Easy to add those corrections to the script and possibly uninstall any commercial modules you might have with " amportal a ma "