provided by Star2Billing S.L.

I use older version of a2b 1.9.4, I have bunch of my own mods in it, so I'm slow to upgrade.
In March 2017 paypal changed some inner workings of checkout and is no longer accepting comma in amount filed.
i.e. 1,000.00 is no longer accepted where correct string would be 1000.00.

The customers received AMOUNT_ERROR if the payment was 1000.00 or more.

What I did to fix it was modify a line from :

tep_draw_hidden_field('amount', number_format($order->info['total'], $currencyObject->get_decimal_places($my_currency))) .

to :

tep_draw_hidden_field('amount', number_format($order->info['total'], $currencyObject->get_decimal_places($my_currency), '.', '')) .

in customer/lib/epayment/methods/paypal.php

Perhaps there is a better way, other then upgade