If you click edit on a swaps page, you may see this error message:
<your name>, you are not authorized to access swaps.nsf/<bignumber>/<bignumber>!EditDocument.
Please sign in with a name which has sufficient access rights.
This seems to be the case with Internet Explorer 10 after you have just logged out and log in again as another id. To avoid this with Internet Explorer 10, use a decent browser like Google or Firefox or shut down Internet Explorer 10 and restart it.
If this doesn't work keep a note of the web address and send it to us using feedback and we will check the page is ok.