Some of the binaries may need to be reinstalled from the source
directories; I had to do that with lilo, for example, since my version
was newer than the one on the Slackware installation and I hadn't
bothered to save the binary from /sbin. You'll want to check through
your restored programs and confirm the existence and correctness of
configuration files, libraries and so on. In some cases, you may have
to restore things in a specific order; you did make notes during
backup, didn't you? ;-)