I followed the instructions and copied the SWF file from the downloaded pro web folder and replaced the one in the photoshop CS4 script simpleviewer folder and when I open photoshop it still shows the free version layout.
This is correct nothing will change, the reason you replace the swf is so that galleries you produce with Photoshop will use the pro version of the swf.
When I open the SVbuilder it says simpleviewer pro 2 must be installed?
If you are trying to edit a gallery in svBuilder, the gallery must have the PRO version of the simplevewer.swf in that gallery's folder. You can update existing galleries by deleting the simpleviewer.swf in the gallery folder and copy the PRO version of the simplevewer.swf from the pro download into the gallery folder.
And now I have no button in the script that lets me create the gallery
In the photoshop script? If so you need to increase your screen resolution.
SimpleViewer Support Team.