Change the URL for the 'back' button in error messages to prevent problems with browser caching (fix for #182)

Signed-off-by: Michael Eshom <oldiesmann@oldiesmann.us>

Themes/default/Errors.template.php

@@ -37,7 +37,7 @@ function template_fatal_error()
 	// Show a back button (using javascript.)
 	echo '
 	<div class="centertext">
-		<a class="button_link" style="float:none" href="javascript:history.go(-1)">', $txt['back'], '</a>
+		<a class="button_link" style="float:none" href="javascript:document.location=document.referrer">', $txt['back'], '</a>
 	</div>';
 }