Also, their Security Space keys do work on Symbian 9.x versions. And you still can get recent VDBs. On a long-dead mobile OS you still get updates!
If you ever going to add some protection to your Windows 98 SE machine, go for Dr.Web 5.0. For Windows 2000 SP4 — Dr.Web Security Space 7. Both still get their VDB updates, but you have to be careful about 98SE: there can be serious performance impacts.