The latest Patches from
www.winmxgroup.com will run with win98 no problem.
The only thing I see that might cause some troubles in your setup is ZoneAlarm, especially if you've chosen to upgrade your winmx at the same time.
It's well known for running fine for ages and suddenly starting to mess up things, and a new installation such as the patch might very well cause your troubles.
The stupid thing about it is, that even when disabled it still acts weird sometimes which can only be fixed by deinstalling/reinstalling ZoneAlarm.
You could try to removing winmx from all your rules in ZoneAlarm, disabling that and trying the installation then.
Otherwise you might consider removing ZoneAlarm completely and installing an alternative like Sygate Personal etc.