An Unexpected Error occurred while upgrading:
#0 /var/www/html/concrete/libraries/3rdparty/adodb/adodb.inc.php(1074): adodb_throw('mysqlt', 'EXECUTE', 1025, 'Error on rename...', 'DROP INDEX mess...', false, Object(ADODB_mysqlt))
#1 /var/www/html/concrete/libraries/3rdparty/adodb/adodb.inc.php(1049): ADOConnection->_Execute('DROP INDEX mess...', false)
#2 /var/www/html/concrete/libraries/3rdparty/adodb/adodb-datadict.inc.php(378): ADOConnection->Execute('DROP INDEX mess...')
#3 /var/www/html/concrete/libraries/3rdparty/adodb/adodb-xmlschema03.inc.php(1737): ADODB_DataDict->ExecuteSQLArray(Array, false)
#4 /var/www/html/concrete/core/models/package.php(206): adoSchema->ExecuteSchema()
#5 /var/www/html/concrete/core/controllers/single_pages/upgrade.php(226): Concrete5_Model_Package::installDB('/tmp/tmpupgrade...')
#6 /var/www/html/concrete/core/controllers/single_pages/upgrade.php(245): Concrete5_Controller_Upgrade->refreshDatabaseTables(Array)
#7 /var/www/html/concrete/core/controllers/single_pages/upgrade.php(59): Concrete5_Controller_Upgrade->do_upgrade()
#8 [internal function]: Concrete5_Controller_Upgrade->view('tools', 'required', 'upgrade.php')
#9 /var/www/html/concrete/core/libraries/controller.php(265): call_user_func_array(Array, Array)
#10 /var/www/html/concrete/core/libraries/controller.php(235): Concrete5_Library_Controller->runTask('view', Array)
#11 /var/www/html/concrete/core/libraries/view.php(781): Concrete5_Library_Controller->setupAndRun()
#12 /var/www/html/concrete/tools/upgrade.php(6): Concrete5_Library_View->render('/upgrade')
#13 /var/www/html/concrete/startup/tools_upgrade_check.php(9): include('/var/www/html/c...')
#14 /var/www/html/concrete/dispatcher.php(143): require('/var/www/html/c...')
#15 /var/www/html/index.php(2): require('/var/www/html/c...')
#16 {main}