When Amikit gets to the Workbench I am now getting an error alert window which says
"To use the GUI you need ClassAct or ReAction. OK"
I don't know what started it or what effect it has but the only option is to click on OK.
How to get rid of this?

What is the title of this window? It should be a name of program that reports this problem. It seems you touched ReAction classes files somehow...

The window only has the title "Error" and the text as above.
There's a little spinning ! in a red circle and an OK button

I have no idea how to help you. Like I said you must have installed something that touched the reaction classes in AmiKit... Try to experiment a little with enabling and disabling programs in WBStartup+Prefs to find out what program is reporting the error... Or simply reinstall whole AmiKit ;)

OK, thanks for the info. I will do that.
The only programmes I installed were Pagestream, ImageFX and Photogenics.
I didn't want to get too deep into installing a lot of stuff as this is only testing Amikit to see if it would meet my needs.
I could go with AmigaForever but there's a lot more work to do to get that to what you have done with Amikit.
Now when I install it on my main machine I think I might like to make hardfiles of around 4.5 GB (DVD size) so I can backup to DVD. I am assuming I can do that., make the hardfile that size and then in Amikit partition it into smaller chunks.