The one that would appear to be missing is ashServ.exe, the main scanning engine I can only assume that this would also show in win98.
And when I go onto Avast on Access Scanner it shows nothing is running and It will not let me start to run anything.
This would confirm why those options were grey, if they aren't any running you can't pause or stop them. If you hover your mouse pointer over the avast icon it will tell you x number providers total x running, what does that say ?
Because the ashServ.exe would appear not to be running it won't let you start the other providers without the main scanning engine (that they use).
See my comments here about defrag in win98
http://forum.avast.com/index.php?topic=24847.msg203547#msg203547.
Personally I think your installation is screwed, sorry for using technical terms.
Try a repair of avast. Add Remove programs, select 'avast! Anti-Virus,' click the Change/Remove button and scroll down to Repair, click next and follow. You need to be on-line to do this.
If that doesn't work try, uninstall, reboot, install, reboot.
It would probably be best to download the latest version of avast and save it to your HDD, somewhere you can find it again. Use that when you reinstall.