LCD together with ArdOS problems

We are using a RTOS ArdOS, and we are trying to use the following LCD library:

It crashes when we are using the method setCursor, and we are suspecting the following method to be the reason:
void LiquidCrystal_I2C::expanderWrite(uint8_t _data){
Wire.write((int)(_data) | _backlightval);

Is there any way to work around this, or somehow fix it so it is compatible with ArdOS, or another RTOS?

I'm also experiencing this problem with ArdOS combined with that library. The library works fine when used without ArdOS, but if the library is used within a task in ArdOS, it crashes the Arduino.. I hope someone can help.