Payment module - cant find certificate file

I have been using the "Zen-Cart Payment Module for PayPal Website Payments Pro V1.2" contri for about 8 months now with very little problems.

Recently, (sometime after 2/19) my direct payment funtion stopped working - reporting: "There has been an error processing your credit card. Please try again. "

I've verified that 'no log file' is generated for the transaction.

At a loss, I looked thru the paypal_dp.php module and have pinpointed the function generating the error (called before_process())

Here is the section of code that is detecting the failure.

$caller =& Services_PayPal::getCallerServices($profile, $logLevel, MODULE_PAYMENT_PAYPAL_DP_LOG_DIR);
if(Services_PayPal::isError($caller))
{
print $caller->getMessage();
$messageStack->add_session('checkout_payment', MODULE_PAYMENT_PAYPAL_DP_TEXT_PROCESS_ERROR . '<!-- ['.$this->code.'] -->', 'error');
zen_redirect(zen_href_link(FILENAME_CHECKOUT_PAYMENT, 'error_message=' . urlencode(MODULE_PAYMENT_PAYPAL_DP_TEXT_PROCESS_ERROR), 'SSL', true, false));
}

I activated a commented debug line that shows the most recent mesage ( print $caller->getMessage(); ) and it reports that the module can't find the cert file (which is there and has access granted).

Could not find certificate file '../etc/ppc/cert_live_pem.txt'

I've made no changes to the site for a long while - this seems to be out of the blue.

Has anyone experienced this problem before or have any suggestions on where to go from here? Much appreciated.

Thanks in advance. Jim

If you're using a 3rd-party addon, you may have to get support from the author for that module.

Zen Cart has a built-in Website Payments Pro (Direct Payment) module as of v1.3.8. It doesn't use the certificate API security ... it uses the signature API security method instead, so you'll have to re-establish your API details.
https://www.zen-cart.com/getpaypal