CB 1.9 upgrade fails step 1 to blank page

Following the README-UPGRADE.txt
Upgrading from CB1.7 to latest CB1.9 on Joomla 1.6.5 stable before upgrading Joomla as per instructions.

1) Install new CB component (com_comprofiler.zip) from
your CB 1.9 distribution package.
Do not uninstall existing CB component.
Previous installation and database will be updated automatically
and all CB fields, Tabs, Plugins, Lists, Configuration and user profile
data will be preserved.

When I do that it takes me to a blank page with URL
/administrator/index.php?option=com_installer&view=install

If I open extension manager in another page after that it still shows CB at 1.7
OK Just found an error log entry:
PHP Fatal error: Call to undefined method JDatabaseMySQLi::qn() in /home/ ... /tmp/install_50e09f7491108/install.comprofiler.php on line 78

Any ideas how to proceed? Thanks

Hello,

Same problem as you, I tried to upgrade to CB 1.9 from CB 1.2.1, but it leave me with a blank page :
/administrator/index.php?option=com_comprofiler&task=finishinstallation
Now when I click on CB in my admin components menu, all pages are blank ! So I'm unable to run CB Tools in order to trigger database modifications...
My Joomla is 1.5.26 version and it run under PHP 5.3
Any help would be appreciated.

OK I succeeded to solve my problem so I reply to myself and give the solution here in case it could help someone else
It was a problem with french language file from CB 1.2.1. My default language is french - which explain my bad english - and french language file from CB 1.2.1 breaks something during CB component update to 1.9. A working solution is to remove french language file before starting to update CB component.
But in my case it was too late, so I had to do some "hack" manually. Inside directory components/com_comprofiler/plugin/language/french I renamed cbteamplugins_language.php file to cbteamplugins_language_OLD.php
After that the CB component in joomla admin worked again, so I was able to do the last step of CB update. I downloaded the new french language file for CB 1.9 from here extensions.joomla.fr/extensions/index-des-extensions-fr/weblink/50/4193/1 and install it as any CB plugin. Then I removed completely the old language file with CB plugin manager.
Hope it could help !

Hi everyone,

I have the same problem as mentioned by 11k.
Any suggestion towards a solution would be welcome.

Thank you in advance