RH ExtendScript bug... Use Window.prompt() and it'll work. The same goes for confirm: Window.confirm() does work. Alert() does work however and prompt and confirm work in ExtendScript toolkit itself.
I've never tried opening a topic in the WYSIWYG and I don't think that RoboHelp supports this. You can open a file with ExtendScript, but that just launches the file in default viewer (probably your web browser). I'll look into opening a topic in the WYSIWYG, but I can't promise anything.
Thanks for the response Willam. I hope there's a way to do this, otherwise I'll have to manually open up all 600+ files in the viewer --- and that'd be a painful loss of time.
Well I found a workaround using a combination of Notepad++ to get a list of filenames with the image in it and then Macro Express to open the topic in RH. Kind of klunky, but it at least does what I need it to do. Very handy tools.