I think this problem only occurs when you try to insert formulas with
an array. In Europe, f you examine a formula in a spreadsheet you'll
see =if(x ; 0 ; 0), in US you'll see =if(x, 0 , 0). As far as I can
tell, Excel isn't smart enough to translate the delimiters when they
are stuffed into an array. Wiser people may have better explanations.

Try this:
control panel -> regional settings -> dutch(belgium)

Then run your program.