I'm getting the following error message when upgrading the site from 5.5.1 to 5.6.2.1. I've upgrade C5 sites more times than I can count but I can't seem to track down this bug. This particular site was built by someone else. Any idea what might be causing this? There is only one add-on installed (Gallerific). And I’ve checked the override folders and they are all empty.

An Unexpected Error occurred while upgrading: #0 /home/content/M/o/u/MountainCft/html/frisco/concrete/libraries/3rdparty/adodb/adodb.inc.php(1074): adodb_throw('mysqlt', 'EXECUTE', 1054, 'Unknown column ...', 'select btID, bt...', false, Object(ADODB_mysqlt)) #1 /home/content/M/o/u/MountainCft/html/frisco/concrete/libraries/3rdparty/adodb/adodb.inc.php(1030): ADOConnection->_Execute('select btID, bt...') #2 /home/content/M/o/u/MountainCft/html/frisco/concrete/libraries/3rdparty/adodb/adodb.inc.php(796): ADOConnection->Execute('select btID, bt...', Array) #3 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/models/block_types.php(359): ADOConnection->Query('select btID, bt...', Array) #4 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/models/block_types.php(315): Concrete5_Model_BlockType::get('btHandle = ?', Array) #5 /home/content/M/o/u/MountainCft/html/frisco/concrete/helpers/concrete/upgrade/version_552.php(24): Concrete5_Model_BlockType::getByHandle('image') #6 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/controllers/single_pages/upgrade.php(251): ConcreteUpgradeVersion552Helper->run() #7 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/controllers/single_pages/upgrade.php(44): Concrete5_Controller_Upgrade->do_upgrade() #8 [internal function]: Concrete5_Controller_Upgrade->view('tools', 'required', 'upgrade') #9 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/libraries/controller.php(264): call_user_func_array(Array, Array) #10 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/libraries/controller.php(234): Concrete5_Library_Controller->runTask('view', Array) #11 /home/content/M/o/u/MountainCft/html/frisco/concrete/core/libraries/view.php(783): Concrete5_Library_Controller->setupAndRun() #12 /home/content/M/o/u/MountainCft/html/frisco/concrete/tools/upgrade.php(6): Concrete5_Library_View->render('/upgrade') #13 /home/content/M/o/u/MountainCft/html/frisco/concrete/startup/tools_upgrade_check.php(9): include('/home/content/M...') #14 /home/content/M/o/u/MountainCft/html/frisco/concrete/dispatcher.php(105): require('/home/content/M...') #15 /home/content/M/o/u/MountainCft/html/frisco/index.php(2): require('/home/content/M...') #16 {main}