use single quotes when creating a rule in the eCart object:
<?php echo (($dmbc_in_stock->TotalColumn('TotalPrice') - ($dmbc_in_stock->GetDiscounts()) *1) * $_SESSION['TaxRate']); ?>
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.