"We have DFD & DFW hosted on a 2000 server and, RDP is served by a 2008 32bit server".
We haven't tested this so it is hard to recommend anything. You just have to try. There is a couple of hurdles.
1. The fact that DFW 5.x is 16 bit and hence won't run on anything higher than 32 bit. This hurdle you have passed. 2. Windows libraries. DFW 5.x was built using an old version of Borland C/C++ I'm not sure how well this will run on a 2008 Server, but one can only try. As you have to run it on the server where the RDP is there is no point keeping the 200 server. You can just move it to the 2008 server. if it runs there you should be home free. 3. Network protocols. Again this is seriously old stuff and MS has a tendency to eradicate old support as they move up. Again you can only try.
Overall, our recommendation would not be to invest any time/money/effort into getting this running in 5.5. It is such an old product and from such an earl stage of Windows that it has been troubled for a long time.
We started a LegEasy program back in 2012 due to the fact that newer products than 5.5 started to have compatibility issues. Our first LegEasy version for LegEasy 6 Windows which is a rebuild of DFW 6.52.
LegEay 6 Windows is built with the latest Borland Compiler and was designed to be compatible with WIndows 7 x64/x86.
It has not been re-certified for any new version of Windows but it has been thorougly tested in Windows 8, 8.1 and 10 and works fine in all of those.
It is not a free upgrade as there are no free upgrades for any product this old. There is an upgrade path from 6.x to LegEasy 6 but not from DFW 5.