Weird Compiler Issue

I'm guessing that speedValue is a float here (maybe it comes from ActivityInfo.currentSpeed?). That makes eteHoursValue a float as well.

In Monkey C, modulus (%) is only defined for integers, which is why your app crashes when you try to use it with a float. In this case, you could replace "eteHoursValue % 1" with "eteHoursValue.toNumber()". Or you could replace "eteHoursValue = drValue / speedValue;" with "eteHoursValue = (drValue / speedValue).toNumber();"

Note that these examples will truncate, not round. If you need to round, use Math.round() in addition to toNumber(). e.g.

eteHoursValue = Math.Round(drValue / speedValue).toNumber();

If you need a version of mod that works with floats and doubles, you could implement your own.

I use something like this, in a data field where I allow the user to enter arbitrary math formulas (like Excel), and mod is one of the operators available to the user:

function mod(x, y) {

  return x - y * Math.floor(x/y).toNumber();

}