The TextLinkAds WP plugin is dynamically generated to insert the API key. I think this dynamic generation may be wrecking havoc with version numbers. I have verified this vulnerabiility in version 3.0.8.
Please do not trust the version number on your WP TextLinkAds plugin, your plugin is likely vulnerable.
The advisory has been updated accordingly.
What about 3.0.9, which i sent you? Cant find something around line 512 which states
$postid = $postid
BloggingTom, looks like they have implemented our fix into the latest version. Thanks for the update.