CMS Made Simple Forums

I have made two main files: main_NL and main_EN. The content is already put in two different directorys. Also the Admin is separated. But when I change the English article in main_EN also the dutch version is changed to main_NL. The News in two languages is working perfect. But now I have Dutch news on my English pages. See http://www.janvermeer.nl
Can anywhone help me?