As far as using the icq98, without trying this, and working on memory,
the ICQ98 used an older protocol, such as v5. Now icq uses v8, an possibly even OSCAR. therefore you prolly will not have any success using the client. Even if it were to successfully login and get you online, anyone who sent you an offline message, you wont receive it.
and alot of people might have their clients set "not to communicate" with less secure clients, such as 98.