payment's image link and error checkout qty

I just noticed these things that i tried to solve myself but failed =(

1) With only one payment method to use, i still show them in checkout page. However the image of payment method (i only use 'bank transfer'. The image we can choose from given images in configuration-payment method-bank transfer-image) is click-able and has the same URL attached as "NEXT" (meaning: end of checkout workflow). So when customer accidentally click on payment's image (which is very often), it brings checkout process to end. When customer does it, 98% of them has not yet checked the shopping cart. Sooooo, simple question, how to remove the url link property of payment's image??

2) When there are 2 customers (1 and 2) shop at website simultaneously or not.. let say item A only have 1 qty left. Both of customers add item A to their shopping cart. Then Customer 1 finished checkout before Customer 2. Then customer 2 checkout, the web will display "500 internal server error" in customer 2 face =) .. Well is there any fix that instead of displaying '500 internal server error', hikashop will display 'item A has inadequate quantity for your order due to bla bla, please bla bla'??
It is ok if they only put 1 item in their cart, easy to detect, but imagine if they have like 20 items in their cart, and we have to check one by one..

I'm in J1.6 and Hikashop 1.4.8

Thanks before Nikolas..