This really sounds like a driver issue, so don't blame SFML...
Anyways it sounds like all the textures get deleted, but verify if it's caused by your code, SFML or some other strange driver issue, you'll need to create a minimal, but complete example that reproduces the error.
Since I've not really any knowledge with OpenGL I can't help you there any further...
Have you ever experienced similar errors with other OpenGL applications?
What's your exact version of SFML 2? RC? Commit XYZ?