Accessing LAN from XP

Hi,

i've setup cipe on windows xp (roadwarrior) in order to access our 
company-lan (redhat7.3).

i am able to ping all machines at the lan with name and ip. i can also 
telnet or ssh to the machines.

but i cannot connect to the network shares at the lan (samba).
i also cannot ping the xp machine from the other (redhat) cipe side.

has anyone a tip for me why? 

regards, wolf