hey,
if you can already open the app but the app has a problem reading "login.dat"
so your solution might be renaming it to be "login.swf" then edit it.. after editing it back it again to "login.dat".
it's working with me in win 10 x64 even JPEXS works, but
if you can even open the app, so use compatibility mode
of just use "Oracle VM VirtualBox" or any other virtual app to install windows 7 for example and use the app