Redirect to white page after submit

The infamous "whitescreen" error is extremely difficult to debug, since it just means there was a PHP error of some sort. You should enable the "display_errors" option in your php.ini file, then PHP will actually tell you what the error is, otherwise this is an extremely hard thing to solve. Regarding downgrading see these issues:

#721662: Downgrading Webform causes "warning: Invalid argument ..." in Form components
#684884: Invalid argument supplied for foreach() in webform_components.inc

Hm. Well this makes things hard to fix since we don't know the problem. The most common cause of such a problem is using the FCKeditor (or CKeditor) module with Webform. This adds a nasty empty <p></p> in every textarea. This can cause a problem when HTML like this is inserted into the "Additional Processing" or "Additional Validation" textareas, since when they are executed, PHP runs into a parse error.

Even if you leave those fields blank, FCKeditor will insert something into them, which is what causes the problem. If you're using either FCKeditor or CKeditor (the modules) then that is the likely cause. Using the WYSIWYG module with either editor is fine.

I was able to fix this problem by deleting the junk that was in the additional_validate and additional_submit columns under the "Webform Advanced Settings" section for this form. The FSCK editor was configured for these two fields and had entered bogus data which caused the problems. I never did find any PHP error messages.

I'm having the same error when uploaded to the server and my memory is set to 128 MB. However I'm not using any editors like FCKEditor or WYSIWG as they had their own set of issues on content display, i have disabled them in the module. When I view the source of the blank page, the content of the original form is still there, is very much there and the mail is also being sent out but i end up with the WSOD. We are to launch the site on Monday - so guided help here would be grateful.

Solved. I checked my logs and it had a few instances of Cannot modify header information - headers ... so i checked the class.smtp.php and class.phpmailer.php and found that both the files which were edited using dreamweaver had trailing line breaks at the end after the ?> so i removed those and it worked. Brilliant. I found the reason on http://drupal.org/node/158043. Hope it helps everyone who is using webforms with phpmailer.

Sounds like everyone is cleaned up here.

Your page template.php must be with :
1-ANSI/UNIX encodage pas en UTF8 !
2-without any space outside ...