Deleting discussion takes to wrong vanilla forum

I installed vanilla in a directory on my server
public_html/mypersonaldir/vanilla
when I delete a discussion, I get 404 error. When I look at the address bar, I see that after deleting discussion, the URL changes to
public_html/vanilla
(mypersonaldir/) is missing from the URL. And hence the 404.

I am using the latest BETA (Version 2.0.18b2)

Thanks