Hello!
I am running Slackware Linux 10.2 with kernel bareacpi.i 2.4.31. My UPS is
inform
GUARD series
line interactive UPS

This is all the info I could extract from my UPS's documentation. I downloaded and installed the NUT Slcakware package nut-1.4.1-i486-1JKv.
The hostname of my system is "marto", the domain name is "mydomain". Apart from the "root", I have one user "marto".
These are my configuration files:
ups.conf:
[InformGuard]
driver = genericups
port = /dev/ttyS0

upsd.conf:
ACL all 0.0.0.0/0
ACL localhost 127.0.0.1/32

ACCESS grant monitor localhost
ACCESS deny all all

upsd.users:
[root]
password = mypass
allowfrom = localhost
actions = SET
instcmds = ALL
[marto]
password = pass
allowfrom = localhost

upsmon master

upsmon.conf:
MONITOR InformGuard@localhost 1 marto pass master
#the other settings in upsmon.conf are the default ones

The problem is that when I run "upsd", the following message appears:

Network UPS Tools upsd 1.4.1
/var/state/ups is world readable
Can't connect to UPS [InformGuard] (genericups-ttyS0): No such file or directory
/etc/upsd.conf is world readable
/etc/upsd.users is world readable
Synchronizing........ giving up

What do you think the problem is? Any solution? Thank you very much in advance.