Are you using some kind of file manager? I've never used one so can't suggest how to fix it using the GUI, but it could be an access rights issue, i.e. you need to tell the O/S that it's an execuable.
Try opening up a command shell to where you've downloaded the installer and type the following (assuming the 32 bit installer is called RegnumOnlineInstall_32):
Code:
chmod 755 RegnumOnlineInstall_32
Then run it with:
Code:
./RegnumOnlineInstall_32