Noticed that on submitting the Free Registration form the site complained with following message:
Deprecated function: Function split() is deprecated in GA_Parse->ParseCookies() (line 80 of ***/ga_tokenizer/class.gaparse.php).
Turned out that the current version of this module uses the php split() function which is deprecated in favor of explode(). This has been changed in the git version, but not in a stable release. See thread at http://drupal.org/node/1198504 which included a patch file for my version of the module.
Downloaded the patch file but the hosting company doesn't have patch! So, downloaded the class.gaparse.php file to home and applied the patch there. Uploaded and tested and it appears to work fine: (1) no warning messages following submit; and (2) the form emails as appropriate.