Hi,
It looks like your script is incorrect. The expression:
path to frontmost application as Unicode text
will produce a string/text object. Surrounding that in curly braces creates a list object with a single element being that string.
You are then trying to "tell" that list object to get its "window 1" element, but list objects have no such elements. Neither would the string object. That's the source of the error you're seeing. Things haven't proceeded to try to set the bounds and you're not addressing the RootsMagic application (except for the activate command).
For the most part, our launcher mini-applications aren't very scriptable. You can work around that by using the System Events suite, which works using the Accessibility API. The system will prompt you for permission to use the Accessibility API. So, you can do something like this:
tell application "System Events"
set theWindow to front window of application process "RootsMagic"
set position of theWindow to {1, 1}
set size of theWindow to {1281, 721}
end tell
(Although the system won't really let you move the window to {1, 1}, since that would put its title bar behind the menu bar. I would recommend setting the Y component to at least 22.)
Out of curiosity, what version of CrossOver are you using and why do you want to script the positioning of the window? Is it because the window comes up filling the screen on every launch? If so, the issue is probably that RootsMagic set its window to be "maximized" the first time it ran and has remembered that setting ever since. Maximizing windows is a Windows thing that doesn't really map properly to the way things work on OS X. Depending on the version of CrossOver, you may or may not be able to move and resize the window when it's maximized. Prior to CrossOver 14, you would be able to move and resize the window, but that didn't technically change whether it was maximized. As a result, RootsMagic would continue to think it needs to maximize the window on launch. Since CrossOver 14, we enforce maximization by preventing moving or resizing the window. You can "unmaximize" the window by selecting Zoom from the Window menu or Option-clicking the green plus button in the window's title bar. (Prior to Yosemite, it wasn't necessary to hold down the Option key, but Apple changed the behavior of that button.) Once you unmaximize it, you'll be able to move and resize it as normal. Furthermore, RootsMagic should remember that it's no longer maximized and its last position, so that it will come up in the same place on next launch.