Dynamic Actions & Cascading List of Values (Exception thrown and not caught

Question

I am having a really strange issue within my Apex 4.0 environment where I am trying to build dynamic actions and cascading list of values.
I am trying to develop new functionality in an existing application, (original application developed using HTMLdb 1.6 and gradually updated to Apex 4.0.1), to add a dynamic action that sets a value of another field, using SQL. The dynamic action is failing with 'Exception thrown and not caught - jquery-1.4.2.min.js Line: 28 Char: 162'. However, when I create a new application within the same workspace and develop the same functionality is works without a problem.
I have ensured the templates for each page/region are an exact copy of each other.
<b>When I run the application in Firebug I get the following information:</b>
Date     Fri, 31 Dec 2010 14:20:03 GMT
Server     Oracle-Application-Server-11g
X-DB-Content-length     87
Set-Cookie     HTMLDB_IDLE_SESSION=31-DEC-2010 23:20:03;path=/
Content-Length     87
Keep-Alive     timeout=5, max=99
Connection     Keep-Alive
Content-Type     text/html; charset=UTF-8
Content-Language     en
<b>For the application that is working I get slightly different response headers.</b>
Date     Fri, 31 Dec 2010 14:20:37 GMT
Server     Oracle-Application-Server-11g
Cache-Control     no-cache
Pragma     no-cache
X-DB-Content-length     14
Content-Length     14
Keep-Alive     timeout=5, max=94
Connection     Keep-Alive
Content-Type     application/json
Content-Language     en
<b>Notice the Content-Type for the version that doesn't work is using "text/html", while the working version uses "application/json"
Firebug also provides the following error:</b>
uncaught exception: Invalid JSON: Content-type: application/json Cache-Control: no-cache Pragma: no-cache {"value":"1"}
<b>Does anyone have any idea what is going on??
Thanks.
Jon</b>

Answer 1

Patrick,
Thanks my session verify function was causing the problem and I have removed it temporarily from my authentication scheme.
I am using the "check_timeout" function that was developed a number of years ago as part of a "How To" section in the old HTMLdb days. I knew there was an issue with this routine as the newer versions of the browsers handle cookies differently and I was going to redevelop it at some point. Do you know which part of the function causes the issue?
Many Thanks,
Jon
FUNCTION check_timeout
RETURN BOOLEAN
AS
l_session_expire VARCHAR2(256) := NULL;
l_cookie_exists BOOLEAN := TRUE;
BEGIN
IF htmldb_custom_auth.get_user IS NULL THEN
RETURN TRUE;
END IF;
BEGIN
l_session_expire := owa_cookie.get('HTMLDB_IDLE_SESSION').vals(1);
EXCEPTION WHEN NO_DATA_FOUND THEN
l_cookie_exists := FALSE; -- no cookie set, assume first page visit after login
END;
IF l_cookie_exists
AND TO_DATE(l_session_expire,'DD-MON-YYYY HH24:MI:SS') < SYSDATE
THEN
wwv_flow.g_unrecoverable_error := TRUE;
owa_util.redirect_url('f?p='||'500:101'); -- Note hard-coded login application and page ID 500:101
RETURN FALSE;
ELSIF NOT g_cookie_already_sent THEN
owa_util.mime_header('text/html', FALSE);
owa_cookie.send ( NAME => 'HTMLDB_IDLE_SESSION',
VALUE => TO_CHAR(SYSDATE+(c_max_idle_minutes/1440),'DD-MON-YYYY HH24:MI:SS'),
expires => NULL,
path => '/',
domain => NULL );
owa_util.http_header_close;
g_cookie_already_sent := TRUE;
END IF;
RETURN TRUE;
END check_timeout;