On exporting SharePoint site contents

I tried exporting SharePoint site contents one day, as I wanted to move the site from existing site collection into a new site collection. I thought using read-only lock for the current site collection before the export, to prevent anyone making chnages while export is running. The site collection top-level site URL is "http://servername". The URL for the site that I'm exporting is a sub site in this site collection is "http://servername/AVI". I wanted to move this to "http://servername/sites/AVI"

I found that this has created a problem for me. The site import did not work as expected. After I created a blank site collection "http://servername/sites/AVI", when I import the sites into this new site collection, it gave me this error message: "The target site http://servername/sites/AVI/AVI does not exist"

This did not happen if I had done my export without locking it first.