my internet connection start spontaneously

Hello!
I'm a newbye,that with a lot of difficulties has configurated his two
machines in a lan( Win98me and linux) with samba and a ppp connection to
internet via isdn ta. everytnig works, but the connection on my linux
machine starts if the modem is turned on, after 1-2 minutes, without
opening mail programs, browser etc.
I need a lan in wich only rarely the computers are connected. they are
mostly disconnected and every machine has is own indipendent connection
to internet.
When this strange thing happens, in the /var/log/messages file there is
something like this: "samba name server solaris (my linux machine) is
now a local master browser for workgroup stz (my lan name) on subnet
192.168.0.2 (ip adress of linux machine, this machine)"
I have a particular /etc/ppp/options file that makes possible to start
intrenet connection only by clicking on a link. If the modem is turned
on, pppd starts, and disconnects after some time (with the idle
command). Here are my /etc/resolv.conf , /etc/host.conf , /etc/hosts
,/etc/ppp/options files:
Rally need help
thank you
marco

nameserver 127.0.0.1
nameserver 198.162.0.1
nameserver 195.110.128.1
# nameserver 127.0.0.1
# nameserver 192.106.166.1
# domain mclink.it

# ppp temp entry

order hosts,bind
multi on

127.0.0.1 localhost
192.168.0.1 max
192.168.0.2 solaris

lock
crtscts
defaultroute
demand

192.168.0.3:192.168.0.4
ipcp-accept-remote
ipcp-accept-local
holdoff 5
idle 100
noauth
noipdefault
usepeerdns
asyncmap 0xa0000
novj