The odd thing is I looked through the source code for the TMSFNCUIPackPkgDEDXE11 package and there's no reference to FMX.TMSFNCGeneralDE that I could see.
FMX.TMSFNCGeneralDE is part of TMS FNC Core. It should be in that repository. If you installed components via the automated installer, you cannot install other packages manually on top, please either uninstall everything and retry with the automated installer, or click manual installation/compilation for every product and then use the packages. The log files will tell you what went wrong during compilation. They can be found in C:\Users\UserName\AppData\Local\tmssoftware\log
Now this is interesting. I tried uninstalling and installing it again and it failed. Then I uninstalled again but then installed the packages in a different order.
Previously, I was installing the FNC UI Pack last. This time I installed it immediately after the Core package. No more errors!