Hello ,
Thank you for posting in the community. You can resolve this issue by downloading the 5.0.1 plugin and referencing it when installing 5.1.1 when asked.
Here is a link to the older plugin msi file:
https://unrealstudio.epicgames.com/UnrealDatasmithSketchUpExporter_5_0_1.msi
If you still have difficulties please contact us directly by filling out a form here:
https://twinmotionhelp.epicgames.com/s/case-community-page
Kind regards,
Vincent B.