If you have an expression which result in devision by zero of RTC report layout, then result is #Error.
You can write a VB function to avoid this issue. First you must write this following method in RTC report.
Open the report layout and got to the Code section of report properties, then you can write this following function in the Code section.
After create the function you can call it in the expression as you need.
Following example for how to call this function in the report layout expression.