Language problem in formula

Hi,

I have a formula where i want to calculate how old someone is. I've a Dutch Windows and a Dutch Microsoft Office 2013 package, but when i put an 'J' (JAAR) in the formula it doesn't work. When i put an 'Y' (YEAR) in the formule it does work. The rest of the formula is in Dutch and works. I believe i checked everything i could to turn the language to Dutch, but it still doesn't work. Any suggestion?

Kind regards,
Jochem van Leur