No video on 2nd monitor of 2 PC on Iogear GCS 1742 Dual Monitor KVS Switch

I have 2 HDMI monitors that are attached to an HP docking station. I’ve attached VGA cables to the monitors and KVM switch as per the instructions, which are attached to switch one. They are working fine. On the 2nd PC, I have VGA cables going to the respective switches. On connection has a dvi to vga adapter to allow for dual monitors. However, I am unable to attach the second monitor although I have connected all cables as per instructions.

Does anyone have any ideas why I am unable to attach the second monitor? Both machines are running WinXP; however the second PC is an older tower, approx. 5 years old. I can’t find anything on the Iogear website.

-kp