The extensions needed to "make the form work" depends on what you want the form to do.
Do you want to email the form:
either use CSS Form Builder and Universal Email, or use the Contact Form Solution Pack.
Do you want to store the information that was entered in a database:
Use CSS Form Builder and DataAssist.
When you say your form dopes not work, do you mean that the email does not send? Ore that the email arrives, but the form information is not included?
If the email does not send, have you set universal email to redirect to another page after sending the email? If so, are you redirected to that page?
You should double check that you are using the correct settings for the SMTP server.
Another thing to try is to eave the from name blank, and only supply a from address.
If your still having problems, please send a copy of your page so I can take a look at the code.