TYPO3 Core

I am unable to create functional forms with either built-in "Mail Form" or extension "Powermail".

Forms are correctly configured and rendered on frontend. Submitting the forms either redirects to home-page; or redirects to the same page, with all the form inputs included in the URL, but information is not sent to assigned e-mail address.

Submitting form without filling any fields, even required ones, results in exact same behavior.

Sendmail test on Install Tool works correctly.

Tested on MacOS X with Safari and Firefox, and Windows XP with Firefox.

Buggy URL:
http://www.novadanca4.com.br/info/contato

Resulting URL when no fields are filled in:
http://www.novadanca4.com.br/info/contato/?tx_powermail_pi1[uid1]=&tx_powermail_pi1[uid2]=&tx_powermail_pi1[uid3]=&tx_powermail_pi1[uid4]=

Resulting URL when all fields are filled in:
http://www.novadanca4.com.br/info/contato/?tx_powermail_pi1[uid1]=celso&tx_powermail_pi1[uid2]=john%40doe.com&tx_powermail_pi1[uid3]=testing+Mail+Form&tx_powermail_pi1[uid4]=lueyv

1. DEBUG SYSTEM INFORMATION - START ###
   HTTP_HOST : novadanca4.com.br
   TYPO3_HOST_ONLY : novadanca4.com.br
   TYPO3_PORT :
   PATH_INFO :
   QUERY_STRING : TYPO3_INSTALL[type]=phpinfo
   REQUEST_URI : /typo3/install/index.php?TYPO3_INSTALL[type]=phpinfo
   HTTP_REFERER : http://novadanca4.com.br/typo3/install/index.php?
   TYPO3_REQUEST_HOST : http://novadanca4.com.br
   TYPO3_REQUEST_URL : http://novadanca4.com.br/typo3/install/index.php?TYPO3_INSTALL[type]=phpinfo
   TYPO3_REQUEST_SCRIPT: http://novadanca4.com.br/typo3/install/index.php
   TYPO3_REQUEST_DIR : http://novadanca4.com.br/typo3/install/
   TYPO3_SITE_URL : http://novadanca4.com.br/
   TYPO3_SITE_SCRIPT : typo3/install/index.php?TYPO3_INSTALL[type]=phpinfo
   TYPO3_SSL :
   TYPO3_REV_PROXY :
   SCRIPT_NAME : /typo3/install/index.php
   TYPO3_DOCUMENT_ROOT : /home/novadanca4/novadanca4.com.br
   SCRIPT_FILENAME : /home/novadanca4/novadanca4.com.br/typo3/install/index.php
   REMOTE_ADDR : 189.33.67.7
   REMOTE_HOST :
   HTTP_USER_AGENT : Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_7; en-us) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Safari/530.17
   HTTP_ACCEPT_LANGUAGE: en-us
   CONST: PHP_OS : Linux
   CONST: TYPO3_OS :
   CONST: PATH_thisScri: /home/novadanca4/novadanca4.com.br/typo3/install/index.php
   CONST: php_sapi_name: cgi-fcgi
   OTHER: TYPO3_VERSION: 4.2.6
   OTHER: PHP_VERSION : 5.2.6
   imagecreatefromgif(): 1
   imagecreatefrompng(): 1
   imagecreatefromjpeg(: 1
   imagegif() : 1
   imagepng() : 1
   imagejpeg() : 1
   imagettftext() : 1
   OTHER: IMAGE_TYPES : 15
   OTHER: memory_limit : 90M
   SERVER: SERVER_PORT : 80
   SERVER: SERVER_SOFTW: Apache/2.2.11 (Unix) PHP/5.2.9 mod_ssl/2.2.11 OpenSSL/0.9.8c mod_fastcgi/2.4.6 DAV/2
   SERVER: GATEWAY_INTE: CGI/1.1
   SERVER: SCRIPT_NAME : /typo3/install/index.php
   SERVER: PATH_TRANSLA:
   T3CV_GFX: image_proc: 1
   T3CV_GFX: gdlib : 1
   T3CV_GFX: gdlib_png : 0
   T3CV_GFX: gdlib_2 : 1
   T3CV_GFX: im : 1
   T3CV_GFX: im_path : /usr/bin/
   T3CV_GFX: im_path_lz: /usr/bin/
   T3CV_GFX: im_version: im6
   T3CV_GFX: im_negate_: 0
   T3CV_GFX: im_imvMask: 1
   T3CV_GFX: im_combine: composite
2. DEBUG SYSTEM INFORMATION - END ###
   (issue imported from #M11329)