When you use the wiki script do you get any errors?
Also how are you creating the page? Are you using web authoring software and then uploading it?
Try working backwards. If you ssh into your domain and use pico to create a blank html and just paste in the wiki text when you run it you should get the Name input box and an email box with two submission boxes underneath.
If you then add in your lines one by one and test it you may see where the problem lies.
Further:- I've just set up an announcement list quickly and used the wiki script. I took out every entry to use the defaults and only filled in the list and domain entries. It seems to be working okay so maybe you need to add a page at a time to set up the responses you require as I mentioned above.
A bit more:- If I want to personalise it a bit for example to change the default 'alreadyon page' I would use:-
Where example.com is my domain name and the announcement list domain.
'lists' is the folder under example.com where I run the form script (the wiki one from)
And, of course 'alreadyon.html' is the customised page I want to use instead of the default one. Actually the DreamHost ones' aren't too bad .
So my skeleton wiki script would be:-
Of course example.com is not the real site it's just the IANA test domain.