I've just uploaded all the WorldPay module files, overwriting the existing files as suggested. I'm now unable to access my admin area. Any suggestions? I think I was on ZenCart 1.3.

Warning: require(includes/application_top.php) [function.require]: failed to open stream: No such file or directory in /homepages/40/d121509422/htdocs/admin/modules.php on line 10

Fatal error: require() [function.require]: Failed opening required 'includes/application_top.php' (include_path='.:/usr/lib/php5') in /homepages/40/d121509422/htdocs/admin/modules.php on line 10