Before making any purchase we strongly recommend you take up the offer to first test drive the software by using the trial version.
The trial version is identical to the registered version, providing a 45 day trial period in which to fully evaluate the software and during that trial period you are entitled to the exact same levels of software support as a registered user.
Also make sure you using the latest version of the Agent SVN as indicated in the About dialog.
Registration of the Agent SVN requires the purchase of an activation key. That activation key will never expire and will also provides between two and four free software upgrades.