Thanks to both of you for responding so quickly to this.
From a user standpoint it would be great if these great plugins could be made to work together. I absolutely must use SEO Ultimate being it has worked so well for me in the past. I would also really love to use Add Link to Facebook, as it is the best way I've seen (in WP) to truly integrate Facebook with a site.
So here is a thought, what if each plugin would write over the current value of og:url instead of adding it to an array? They are both inputting the same value, the problem is it is added twice.
For anyone else trying to run both of these, at this point, turning off OGP in Add Link to FB seems to cause more problems (missing images, etc) than just leaving it on and accepting the FB error. With both running, and OGP on I haven't noticed any problems so far, despite the error.