Can I use PDFBuilderASP on a 64-bit operating system?

Yes, but a different procedure is required to register and configure the component before use. A COM+ application must be configured for the component in Component Services. If you do not how to do this, this article on the Chestysoft web site explains the steps in detail. Note that it is important to check the "Allow IIS Intrinsic Properties" box, otherwise PDFBuilderASP will fail when using the BinaryWrite command.