If BirdieSync setup file version is not the expected one or if the setup file is corrupted, you may try to clean the cache of your browser and to try to download BirdieSync again:
For instance in Firefox, it's "Tools/Advanced/Network/Empty cache now"
In Chrome, it's "Settings/Advanced Settings/Clear bowsing data/Empty the cache"
In Internet Explorer, it's "Tools/Internet Options/General Options/Deletes.../Temporary Internet Files/Delete files..."

If you have parental control enabled, temporarily disable it and try to download BirdieSync again.

You may also try to download BirdieSync with another browser or from another computer.