Twitter does that sometimes - I've been able to post this morning, so I don't think it's a systemic issue - have you been able to do so since?

hmm...perhaps a browser pop-up issue? I'm on XP, using Chrome 4.x right now, and I just authenticated to both MySpace and Twitter. Do you have a popup blocker on? If so you might turn it off to test this, or just add my.pogoplug.com to the safe list.

ok - this is a longshot, but on one of the XP machines you might try starting from scratch. Sign out of Twitter in Media Settings, then clear the entire history and cache (cookies, etc) of the browser. Shut it down and restart it, then go back in and see if that works. Maybe there's a bad cookie in there or some other preserved setting that is bad and needs to be flushed. If that doesn't work send in a ticket to support and we'll work with them to isolate the problem.

Now that is intriguing! We'll investigate here and see if we can't reproduce your problem. If that is the case, there is a solution, albeit not a great one - you could attach the drive to your cpu and delete the folder called .cedata and the file called .ceid - those are the database and unique identifier of the drive, respectively, for the Pogoplug. The bad part of that is it will force all thumbnails to regen and all videos to retranscode (if you have a lot of media it can take awhile) but if that is the issue, that should resolve it.

I'll write back here if I can confirm that that is the issue.