Hi, Danny.
Thank you for contacting us.
All available translations are listed here:
www.jomsocial.com/translations
4.3 was released few hours ago... so I guess that translators didn't had time yet to translated it to 100%.
Hi, Danny.
Don't give up :) You may translate if by yourself.
JomSocial is shipped with English by default all other translations are contributed by community - thus we can't be responsible for translation correctness or completeness. There was just no one that wanted to maintain this language pack... maybe you want it?
HI, Danny.
One last option is to post on our Community and contact with other Dutch speaking users to share you translation pack with you.