Error while compiling the version 3.1.1?


I use the arduino V1.0.3 compiler for windows and the last version of ArduPlane V3.1.1b.

The compilation process works well and I can make the hex file.

In order to toggle an output digital pin , Unfortunately, a compilation error occurs
"error: ‘digitalWrite’ was not declared in this scope".

I have gone through the internet and tried all the possible solutions but could not get any fruitful result.
Any ideas to solve this problem?

Thank you for your help.