The string _UE_USERREJECT_SUB seems to be missing from default_language.php... The note I got when testing the reject workflow had a subject of:
[website name]-_UE_USERREJECT_SUB
using 1.0RC2 on Joomla 1.0.7

Here's a grep search for that constant, showing the reject strings referenced and defined (but missing this one):

---

grep -i -t -m UE_USERREJECT_ *.*

$cbNotification->sendFromSystem(cbGetEscaped($uid),_UE_USERREJECT_SUB,sprintf(_UE_USERREJECT_MSG,$mosConfig_sitename,$_POST));
mosRedirect(sefRelToAbs('index.php?option=com_comprofiler&task=pendingApprovalUser'),(count($uids))?count($uids)." "._UE_USERREJECT_SUCCESSFUL:"");
DEFINE('_UE_USERREJECT_MSG','Your registration at %s has been rejected for the following reason: \n %s');
DEFINE('_UE_USERREJECT_SUCCESSFUL','The user(s) have been successfully rejected!');

Ah, I just scanned the bug list and see that artf2193 covers this report. Nevermind!