I'm so glad you posed this question - I'm having the exact same problem. I just submitted a question to the PogoPlug support email, but I thought I'd check the forums to see if anyone else was having this problem. This issue began yesterday for me - I've tried restarting my system, my pogoplug, my HDD, my browser, trying Safari, trying Firefox, trying a different computer - all with no luck. I have a feeling it's a behind-the-scenes problem as it sends out an email to the people you are inviting, but they don't have permission to view the files because the system never recorded them. I hope it gets corrected soon.

thanks for the updates, we have fixed this issue. please give it a shot and let us know if you have further issues

I was having the same problem earlier today. The problem seems to be fixed now but I am unable to select the enable upload box next to the account name. The column that hold the user names has expanded into the folder list field slightly so when I put the mouse over the check box the folder is selected instead of the check box. Is any one else having this problem? I am using IE8.