VPN & windows98

hi… i have made a vpn with two mikrotiks like suggested in the manual (PPTP & EOIP)

from one mikrotik i can ping the other one, and the computers in the other lan too. From the other too.

all pcs have windows 98.
one lan has only 1 pc. and sometimes can see others computers and sometimes can’t. why? has someone had a similar problem? is it due to MT or to win98?