I'm getting a popup message on the EPDM fly-out every time I save this DWG/ASM.

It appears to point at nothing at all..... There is no button in this location and I've never heard of this command.

I'm willing to clean up the references of this assembly that I've inherited, but can't figure out what command they are referring to. What is this madness!?

It states:

Update Toolbox References

The assembly contains toolbox parts that are not stored in the file vault. Use this command to update the toolbox references in the current assembly so that they point to the file vault.