Okay, I figured out, it was happening because I had enabled the cache. I disabled it and it worked.
One more thing I noticed, I tried 2 things:
The system did not show me error when I clicked on submit without filling any info, I also entered invalid email address...
Edit: Okay, here are some more bugs....
When you have xx inactive members and 0 are older than 48 hours, and you click on the link to delete them, it shows following error:
Warning: Missing argument 1 for removebulk() in /home/youth/public_html/assets/modules/koopsmailinglist/functions.php on line 191
Warning: Missing argument 2 for removebulk() in /home/youth/public_html/assets/modules/koopsmailinglist/functions.php on line 191
Fatal error: Call to a member function on a non-object in /home/youth/public_html/assets/modules/koopsmailinglist/functions.php on line 195
Edit 2: Oops one more
serious bug, when you enter email address without @ i.e. just the name, the script adds hostname of the server with @ and subscribes the same i.e. if you have entered deep it will subscribe email deep@my_server_hostname.com I got to know about it when I got an email just now to my mailbox...
I hope these pointers help you to make this module stronger.
Edit 3: I wish to use this plugin the side bar of my menu and with no radio buttons for subscribe or unsubscribe i.e. default subscribe should be passed. Can you suggest me how I can do it?
Thanks
Deep
P.S. One suggestion, why not show option for newsletter at the time of registration? If members have checked it, it will add them in the list.