Clicking the civicrm/extern/url.php links on a CiviMail permalink page gives "Missing input parameters"

See forum post http://forum.civicrm.org/index.php/topic,20360.0.html

In a CiviMail, the links of the form .../civicrm/extern/url.php work correctly since both the 'u' and 'qid' parameters are supplied.

However, if I visit the permalink page, those links fail since only the 'u' parameter is supplied.

The solution options are to either get civicrm/extern/url.php to work without the 'qid' parameter, or to somehow supply it. I don't think the second option is valid since permalink pages can be made publicly visible, and 'qid' is not meaningful in that case.

In the forum thread I suggest a fix which does the following if 'qid' is not present ...

• retrieve the URL solely on the basis of the 'u' parameter
• skips the creation of the "click through" event

I haven't yet tested that fix.