An Unexpected Error occurred while upgrading (from 5.6.0.2 to 5.0.1.2)

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when i try i have this message.
An Unexpected Error occurred while upgrading: 
#0 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/libraries/3rdparty/adodb/adodb.inc.php(1037): adodb_throw('mysql', 'EXECUTE', 1062, 'Duplicate entry...', 'insert into Pag...', false, Object(ADODB_mysql)) 
#1 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/libraries/3rdparty/adodb/adodb.inc.php(993): ADOConnection->_Execute('insert into Pag...')
#2 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/models/page.php(2046): ADOConnection->Execute('insert into Pag...', Array) 
#3 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/models/single_page.php(167): Concrete5_Model_Page->addStatic(Array) 
#4 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/helpers/concrete/upgrade/version_561.php(16): Concrete5_Model_SinglePage->add('/dashboard/syst...') 
#5 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/controllers/single_pages/upgrade.php(247): ConcreteUpgradeVersion561Helper->run() 
#6 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/controllers/single_pages/upgrade.php(44): Concrete5_Controller_Upgrade->do_upgrade() 
#7 [internal function]: Concrete5_Controller_Upgrade->view('tools', 'required', 'upgrade') 
#8 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/libraries/controller.php(224): call_user_func_array(Array, Array) 
#9 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/libraries/controller.php(196): Concrete5_Library_Controller->runTask('view', Array) 
#10 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/core/libraries/view.php(743): Concrete5_Library_Controller->setupAndRun() 
#11 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/tools/upgrade.php(6): Concrete5_Library_View->render('/upgrade') 
#12 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/startup/tools_upgrade_check.php(9): include('/homez.509/inge...') 
#13 /homez.509/ingenierb/www/updates/concrete5.6.1.2_updater/concrete/dispatcher.php(82): require('/homez.509/inge...')


How to to ?

Please can you help me ?