cant get to internet with my amilo M1425

i have an FS Amilo M1425. and i am using an airties RT-205 modem. it is connected to another PC via LAN. and the laptop is connected wireless. i can open msn and use it but it wont open any web pages or connect to servers (laptop ). but the pc works fine.
and if i try to connect the notebook via the same LAN the problem doesnt resolve.
the modem is workin fine.
can anyone help me about this?