Can't install prestoserve 2.4.2 on Ultra running Solaris 7

The postinstall script shows the following errors


## Executing postinstall script.
                Prestoserve(TM) - Sparc Release 2.4.2
Copyright (c) 1989-1992 by Legato Systems, Inc.  All rights reserved.
Copyright (c) 1993 by Sun Microsystems, Inc.  All rights reserved.

NOTICE: presto_chango: /usr/man/man1m doesn't exist
        * * * Prestoserve man pages will not be installed
        * * * Installing Prestoserve device driver
drvconfig: Driver (pr) failed to attach
Warning: Driver (pr) successfully added to system but failed to attach
        * * * Adding Prestoserve changes to system files
        * * * Installing Prestoserve files
        > > > Ready to install Prestoserve board in system < < <

        Prestoserve partially installed on test3!

Installation of <SUNWprsto> was successful.

When we attempt to add the driver by hand we get

test3 78 # set drivername=pr
test3 79 # add_drv -m '* 0644 root sys' -i 'MMI,prestoserve SUNW,nvmemory 
SUNW,nvone SUNW,nvtwo' ${drivername}
(MMI,prestoserve) already in use as a driver or alias.

We could see the prestoserve board by typing show-devs at the ok prompt.

The user needs to boot Solaris 7 in 32-bit mode and set the
following line in etc/system file:

set fas:fas_enable_sbus64=0

Device drivers written for 32-bit Solaris do not work under 64-bit Solaris.