delete plug-in options-framework then error has been gone.
but I still have error to change my theme.
Fatal error: Uncaught exception ‘Less_Exception_Compiler’ with message ‘.rgba is undefined in /home2/bckoreac/public_html/s2curity/wp-content/themes/dt-the7_v.3.2.2/dt-the7/css/custom-old-ie.less’ in /home2/bckoreac/public_html/s2curity/wp-content/plugins/wp-less/vendor/oyejorge/less.php/lib/Less/Tree/Mixin/Call.php:148 Stack trace: #0 /home2/bckoreac/public_html/s2curity/wp-content/plugins/wp-less/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php(147): Less_Tree_Mixin_Call->compile(Object(Less_Environment)) #1 /home2/bckoreac/public_html/s2curity/wp-content/plugins/wp-less/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php(88): Less_Tree_Ruleset->EvalMixinCalls(Object(Less_Tree_Ruleset), Object(Less_Environment), 1) #2 /home2/bckoreac/public_html/s2curity/wp-content/plugins/wp-less/vendor/oyejorge/less.php/lib/Less/Tree/Ruleset.php(94): Less_Tree_Ruleset->compile(Object(Less_Environment)) #3 /home2/bckoreac/public_html/s2curity/wp-content/plugins/wp-less/vendor/oyejorge/less.php/lib/Less/Parser.php(187): Less_Tree_Rules in /home2/bckoreac/public_html/s2curity/wp-content/plugins/wp-less/vendor/oyejorge/less.php/lib/Less/Tree/Mixin/Call.php on line 148