Can you go to the file where the issue is arising - includes/modules/payment/as2checkout.php.

Then copy and paste line 315-> 320. Line 318 should only be a bracket, with the end of the file on line 319.

If this isn't the case, you may have a corrupt download. It may be worth removing these files, downloading a fresh copy and installing it again, jsut in case the download is corrupt.

Good luck

Absolute