avidscavenger:

As the fuser man page says:

-m name specifies a file on a mounted file system or a block device that is mounted. All processes accessing files on that file system are listed. If a directory file is specified, it is automatically changed to name/. to use any file system that might be mounted on that directory.

I suspect the way your encrypted partition is mounted is causing your problems with Easy Debian.

A simple workaround for your problem is to find the line in /sbin/closechroot that says:

and stick a # at the beginning. Then add another line, so it looks like this by the end:

This will make the closechroot not use the -m option at all.