Buck,
First, the user interface in PowerSDR mRX is horribly misleading. You can NOT set the IP address of the radio by merely typing it in there. You have to use HPSDR Programmer or HPSDR Bootloader to program the IP address of the radio.
I'm going to make suggestions based on the following assumptions: you have no idea what the IP address of the radio is, and you are not familiar with common methods to figure that out. So what I'm going to suggest is to go "nuclear" on the problem and use HPSDR Bootloader to set the radio address. In addition, this solution will basically require you to have everything tied together: router, switch, PC, radio, so that the router can automatically assign addresses using DHCP to both PC and radio.
HPSDR Bootloader Instructions:
1. Do not use a managed (layer 2 or layer 3) switch. The MAC that the radio uses in bootloader mode is illegal and managed switches will not forward packets. Use a direct connection or a dumb switch (this should not be problem with your switch).
2. If you have more than one network interface card (NIC) in your PC (including Wi-Fi), set your network metrics manually per the guidance here:
http://www.w1aex.com/anan/anan.html#metric3. Download and install
WinPCAP (Bootloader requires it, you will have to restart after install).
4. Download and install
HPSDR Bootloader.
5. Power off radio.
6. Place jumper on board or flip bootloader switch to bootloader position, depending on the radio (on your 200D it will be the switch on the bottom--you may want to mark the positions with some tape, since they are unmarked to start with, I suggest "Normal" and "Bootloader").
7. Power up radio.
8. Run Bootloader.
9. Click "Test for Bootloader". Bootloader should discover the radio.
At this point you can use the Bootloader to change the IP. Click the IP button. Set it to 0.0.0.0 for DHCP operation. Save that into the radio.
10. Quit Bootloader.
11. Power off radio.
12. Remove jumper or flip bootloader switch back to normal position, depending on the radio (on your 200D flip the switch on the bottom back to the "Normal" position).
13. Power up the radio. If the router, switch and radio are all connected, the radio should get a proper address via DHCP and be reachable from your PC.
In PowerSDR select "Reuse last address".
73,
Scott