Hi Nina,
Hold your process after reading the values and have a look at the variables you are calculating with later. Make sure the variable types of the variables you are reading in Excel are correct.
Probably it is also the issue between languages German and English, where the separator differs (,) and (.). You can change the separator with .Replace(“.”,“”).Replace(“,”,“.”).
This would first eliminate your “thousand separators” and then replace “,” with “.”.