Added check to make sure that uid does not already exist. This is

usually handled via uid cookie we get back from the browser, but if
the user Clicks stop or maybe has cookies off, we don't that info.

www/joinproject.php3

@@ -413,6 +413,9 @@ if (! $returning) {
     elseif (!TBvalid_uid($formfields[joining_uid])) {
 	$errors["UserName"] = TBFieldErrorString();
     }
+    elseif (TBCurrentUser($formfields[joining_uid])) {
+	$errors["UserName"] = "Already in use. Pick another";
+    }
     if (!isset($formfields[usr_title]) ||
 	strcmp($formfields[usr_title], "") == 0) {
 	$errors["Title/Position"] = "Missing Field";

www/newproject.php3

@@ -568,6 +568,9 @@ if (! $returning) {
     elseif (!TBvalid_uid($formfields[proj_head_uid])) {
 	$errors["UserName"] = TBFieldErrorString();
     }
+    elseif (TBCurrentUser($formfields[joining_uid])) {
+	$errors["UserName"] = "Already in use. Pick another";
+    }
     if (!isset($formfields[usr_title]) ||
 	strcmp($formfields[usr_title], "") == 0) {
 	$errors["Title/Position"] = "Missing Field";