A new version is installed

When i try to return the previous version (5), there is a message "a new version is installed" which not allow me to complete the instalation. Please advise me how to do it.
 
If i uninstall the new version and install from zero the version 5 i will loose the settings and all saved FTP accounts i have there??

You need to uninstall the new version first. You will not lose any of your favorites.