Why i do get this type of fatal exception when i try to run program

i get the following error often....when i try to run the code...

      Fatal error: Uncaught Error: Access to undeclared static property: Phalcon\Debug::$_isActive in [no active          file]:0 Stack trace: #0 [internal function]: Phalcon\Debug->onUncaughtException(Object(Error)) #1 {main} Next Error: Access to undeclared static property: Phalcon\Debug::$_isActive in [no active file] on line 0 ( ! ) Error: Access to undeclared static property: Phalcon\Debug::$_isActive in [no active file] on line 0 Call Stack #TimeMemoryFunctionLocation 10.0100420776onUncaughtException ( )...(null):0