XDForum – Error 404 not find

I had downloaded the XDForum version 1.4 plugin, follow the instruction and upload it to my server and active the plugin, as well as updated xdforum setting. But the forum link doesn’t work and show up error 404 not find.

I try to changed the permission of it, but also doesn’t work and it always come back to 777. I read couple of previous post about this plugin, but couldn’t figure out where is going wrong?

Can anybody give me a hand?

Thank you.