After a lot of experimentation and reading the Viaklix documentation, etc etc etc, I found out that the redirect get method returns the client to the following url:
...index.php?main_page=checkout_process?ssl_result=0&ssl_result_message...
the problem is with the ? after the checkout_process. It should be a & as shown:
...index.php?main_page=checkout_process&ssl_result=0&ssl_result_message...
if you try it, get the observed error, then make the change, it takes you to the correct screen and everything is processed appropriately. The question now is how to correct the mistake before it happens.
...
I found a solution.
The following code needs to be modified in the viaklix payment moduel (includes\modules\payment\viaklix.php)
Code:
zen_draw_hidden_field('ssl_result_format', 'HTML') .
zen_draw_hidden_field('main_page', 'checkout_process') .
zen_draw_hidden_field('ssl_receipt_apprvl_method', 'REDG') .
zen_draw_hidden_field('ssl_receipt_decl_method', 'REDG') .
zen_draw_hidden_field('ssl_receipt_apprvl_get_url', zen_href_link(FILENAME_DEFAULT, '', 'SSL', FALSE)) .
zen_draw_hidden_field('ssl_receipt_decl_get_url', zen_href_link(FILENAME_CHECKOUT_PAYMENT, 'payment_error=' . $this->code . '&viaklix_cc_owner=' . urlencode($_POST['viaklix_cc_owner']) . '&passedvars=coming' , 'SSL', FALSE));
if (MODULE_PAYMENT_VIAKLIX_TESTMODE == 'Test') $process_button_string .= zen_draw_hidden_field('ssl_test_mode', 'TRUE');
//$process_button_string .= zen_draw_hidden_field(zen_session_name(), zen_session_id());
Also, you need to make changes on the viaklix side.
Go to Terminal Setup -> Payment Form Field Setup
In the Order Information section, select "Add New Field"
make the name and display name "zenid"; Max char 100; ONLY leave the bottom two boxes checked; select "create field"
Add another field.
mae the name and display name "main_page"; max char 50; ONLY leave second to last box checked; select create field
Credit: I looked at OSCommerce support forums a bit. They had a similar problem and solved it their, but it took a lot of reading and trial and error.
you can checkout my cart at www.icaptech.com. I'm proud of it, and the product.