Good morning. Unfortunately, all Dynaserv products were discontinued several years ago and our ability to support them is limited. However, I can offer you a couple of pointers.
I see that you are using a USB-RS232 converter with a Prolific chipset. What we have found over the years is that these often do not meet our expectations of performance and reliability. We recommend using USB-RS232 converters with FTDI chipsets instead. If you need a recommendation, consider using USB-2920 from Cables Unlimited.
Alternatively, it looks like you have an RS232 port built into your PC (COM 1). Is there a reason you are not using this one? Built-in ports usually work better than anything else.
I also notice you are using Windows 7. None of the Dynaserv software was ever tested on Windows 7 and there may be issues we do not know about. Until this January, Windows 7 was also receiving updates, which could result in previously functional software developing problems.
If you have access to a Windows XP computer or a Windows XP virtual machine, I would recommend giving that a try. XP is friendlier with older software than 7 is.
I would also suggest starting to look for a replacement fort this system since the drives and motors can no longer be repaired. Since most Dynaserv systems were pretty specialized, this is something we would want to talk over. If you are interested in replacing this, please reach out to us at firstname.lastname@example.org any time.