Hi, Sorry you are having trouble. You can find the most recent versions of the source for the UE4 plugin on Github.
For example, the last updates for the plugin for Houdini 15.5 was for UE 4.15:https://github.com/sideeffects/HoudiniEngineForUnreal/tree/Houdini15.5-Unreal4.15
There is also a branch which is compatible with 4.14.3:https://github.com/sideeffects/HoudiniEngineForUnreal/tree/Houdini15.5-Unreal4.14
SideFX no longer updates the plugin code for Houdini 15.5. For Houdini 16.0 we are trying to support the 2 most recent versions of UE4, which is currently 4.17 and 4.16. Binary builds of those are included with the Houdini installer.