Un grand merci à ceux qui auront pris 5 minutes pour réfléchir à mon problème, la réponse est tellement simple que j'ai un peu honte de la poster ... il ne fallait pas préciser le répertoire:

cd /var/spool/pkg; pkgadd -d logrotate-3.7.6-sol9-sparc-local

The following packages are available:
1 SMClogr logrotate
(sparc) 3.7.6

Select package(s) you wish to process (or 'all' to process
all packages). (default: all) [?,??,q]: 1

Processing package instance <SMClogr> from </var/spool/pkg/logrotate-3.7.6-sol9-sparc-local>

logrotate
(sparc) 3.7.6
Fidelis Assis
Using </usr/local> as the package base directory.
## Processing package information.
## Processing system information.
4 package pathnames are already properly installed.
## Verifying disk space requirements.
## Checking for conflicts with packages already installed.
## Checking for setuid/setgid programs.

Installing logrotate as <SMClogr>

## Installing part 1 of 1.
/usr/local/doc/logrotate/CHANGES
/usr/local/doc/logrotate/COPYING
/usr/local/doc/logrotate/README.Solaris
/usr/local/doc/logrotate/examples/logrotate-default
/usr/local/doc/logrotate/examples/logrotate.cron
/usr/local/doc/logrotate/logrotate.spec
/usr/local/man/man8/logrotate.8
/usr/local/sbin/logrotate
[ verifying class <none> ]

Installation of <SMClogr> was successful.