errno(3) numbers can be found in GNU/Linux in this file:
$ grep 22 /usr/include/asm-generic/errno-base.h
#define EINVAL 22 /* Invalid argument */
The error in this case is saying that fsarchiver is not able to restore the extended attributtes of the files.
Mandatory Access Control (MAC) attibutes, as implemented by SELinux, are stored in the
xattr of the file(s)/directory.
From the fsarchiver wiki:
It's also important that you make sure that SELinux is not enabled in the kernel running FSArchiver when you save a file-system which has been labeled by SELinux, or you can use FSArchiver with SELinux enabled if you are sure that the context where it's running has enough privileges to read the extended-attributes related to SELinux. In the other cases, the kernel could return unlabeled instead of the real value of the security.selinux attribute. Then FSArchiver would not preserve these attributes and then the system would not work when you restore your root filesystem, or you would have to ask the SELinux to relabel the file-system. The SELinux support is disabled by default if you use FSArchiver from SystemRescueCd-1.1.3 or newer, so your SELinux labels will be preserved if you use FSArchiver from that environment.