Hi and welcome to the forum. We're sorry for the inconvenience.
What Mac you have and which macOS, please?
Anyway, before you click the Start button, go to Miscellaneous settings and enable "Create winuaelog.txt log"
After it crashes, please send us winuaelog.txt, winuaebootlog.txt and the latest .dmp file. You can find them in WinUAE folder (press right-click on AmiKit app, select Show package content and navigate to Contents > MacOS > AmiKit.bottle > drive_c > AmiKit > WinUAE).
Send the files to email@example.com
PS: Does it also crash if you don't select that ISO?