I can reproduce this very reliably by using the satellite to view Nauvis's surface while I am in Nauvis Orbit riding a Space Spidertron. I have some linked remotes that I was trying to use to control one of my planet-side Spidertrons, but upon trying to order it to move somewhere, I see the following error:

The mod Spidertron Dock (1.0.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event spidertron-dock::on_player_used_spider_remote (ID 171)
__spidertron-dock__/control.lua:621: attempt to index local 'spider_data' (a nil value)
stack traceback:
    __spidertron-dock__/control.lua:621: in function <__spidertron-dock__/control.lua:587>

Happy to provide any information that could help, or test a bugfix. (I'd even be fine with manually applying a diff somewhere to help debug / test a fix.)

I just did some testing and I believe this is because the Spidertrons I'm attempting to control were created before I installed this mod. If I destroy and re-build a Spidertron, I become able to control it via its remote, but the other Spidertrons still show the same error. I was able to fix this for me by adding the following code just above the local spider_data assignment around line 590:

            if not global.spiders[spider.unit_number] then
                global.spiders[spider.unit_number] = create_spider_data(spider) 
            end

This might not be the best solution, but it fixes it for me. (I assume that if the spider is valid at this point, then it's probably safe to add it to the global.spiders table, but maybe I'm wrong and this will break for me down the line.)

Not sure how you got into this state, but should be fixed in the latest release. Thanks for the report!

Confirmed fixed! Thanks for the quick response :)