Hi,
I was running 1.2.68 and joomla 1.6.2
as explained in the FAQ I've uninstalled the patches
then I upgrade to joomla 1.6.3
then I installed 1.2.69 on top of 1.2.68 as explained in the FAQ.
The installation process went correctly (no error message).
Now I've when I go to the component Mutlisite component I get an error 500

"JDatabase patch is not installed"

Call stack
# Function Location
1 JAdministrator->dispatch() /home/megaplan/public_html/JOOMLA_MASTER/administrator/index.php:47
2 JComponentHelper::renderComponent() /home/megaplan/public_html/JOOMLA_MASTER/administrator/includes/application.php:153
3 require_once() /home/megaplan/public_html/JOOMLA_MASTER/libraries/joomla/application/component/helper.php:156
4 JController->execute() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/admin.multisites.php:102
5 MultisitesController->manage() /home/megaplan/public_html/JOOMLA_MASTER/libraries/joomla/application/component/controller.php:684
6 MultisitesViewManage->display() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/controller.php:97
7 JView->display() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/views/manage/view.php:147
8 JView->loadTemplate() /home/megaplan/public_html/JOOMLA_MASTER/libraries/joomla/application/component/view.php:180
9 include() /home/megaplan/public_html/JOOMLA_MASTER/libraries/joomla/application/component/view.php:582
10 Site->isNewExtensions() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/views/manage/tmpl/default.php:101
11 Site->_countTables() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/classes/site.php:270
12 Jms2WinFactory->getMultiSitesDBO() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/classes/site.php:190
13 Jms2WinFactory->getMasterDBO() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/libraries/joomla/jms2winfactory.php:528
14 Jms2WinFactory->_createDBO_BasedOnConfig() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/libraries/joomla/jms2winfactory.php:481
15 Jms2WinFactory->_getSingleDBInstance() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/libraries/joomla/jms2winfactory.php:441
16 JError::raiseError() /home/megaplan/public_html/JOOMLA_MASTER/administrator/components/com_multisites/libraries/joomla/jms2winfactory.php:354
17 JError::raise() /home/megaplan/public_html/JOOMLA_MASTER/libraries/joomla/error/error.php:250

Since I can't access to multisite I can't apply the patches...

If you have the "JDatabase patch" not installed, when you are logged in the back-end of the master, go directly in the multisites -> check patches menu to install the patches.

If you try to go in multisites and after want to go in the sub menu "check patches" you will fail.

So you have to go directly to the appropriate sub menu to be able install the patches.