The first message comes from the Wacom driver software, and can occur when you launch an application which uses the tablet ( such as ArtRage ) if there is a problem with this driver. Reinstalling the tablet software may help with this, or downloading the latest version from Wacom's website. If it doesn't, it would be worthwhile contacting Wacom support to help fix that.
The other message is ArtRage failing to see the tablet driver, likely as a result of the first problem. We removed the tablet check in ArtRage 2.5.20, so you can download this latest version from www.artrage.com/artrageinstaller.html and install that instead to get rid of the tablet message. While that won't help with the first problem, it will allow ArtRage to load again, and get rid of that second message.
I hope that helps!