Since your panelview uses DH485, you can't upload directly from the port as you have found.
You will have to use an alternate method, like the memory card.
If you have a 1747-PIC module you could use that as an interface, but there can be problems using it's driver with Windows XP SP3. If you have another method of connecting your PC to the DH485 network, then you can do it that way, (like the 1747-UIC).
If you can connect to the SLC channel 0 serial port, then you can clear bit S:34/6 to allow pass through, and then upload and download through the SLC serial port.
It really depends on what tools you have access to. The memory card is my favorite, and will work with all Panelview standard terminals except the 300 micro. It is also the fastest, and you can easily teach Joe the maintenance tech how to use it to replace a failed unit and get it up and running the quickest...
Paul