The two messages were created at the same time in my last game session (I remember seeing them pop, back-to-back), one an ErrorTrap message, and the other one from Go Here. Both have language about "a null value was found where an object instance was required." What's going on? Do I have any cause for concern?

Those do look like the same error, but they might not be.

The GoHere error is complaining about Chase Bayless becoming unroutable while being pushed to go home. This doesn't look serious if it's a one-off.

The ErrorTrap error is complaining about Cory Simpson, a sim with no household and no valid location in the game.

Now that I think about it, since the errors were back to back maybe Cory was the NPC driver (cab driver?) for Chase at the time something went wrong. Again, that doesn't sound serious unless it keeps happening repeatedly.

OK, I'll resume play and keep my fingers crossed all is well.

Cory was indeed the driver that bounced Chase. It's harmless. But if you start having problems with Sims going to and from lots, you'll want to delete Cory. He seems to have lost his household assignment and the game is unhappy.

OK; I'll keep an eye on it.