Combine wordpress and opencart

Hi all,

I’ve already installed wordpress at root folder on my host, and also installed opencart at subfolder that named “shop/”. I actived permalink feature for wordpress and it’s ok. And I actived the SEO url for opencart. After that, I check some url of opencart, and I see that the url was rewritten, but the display page is 404 page of wordpress. I think it is the conflict between seo url modes of wordpress and opencart. I don’t know how to resolve it. So I come here and find the answer. If you know, please show me how to do. Thank so much and sorry for my english!