So, I've searched the forums and come across people with this error many times, but most of them seem limited to people wishing to entirely change their keyboard layout, which is a little different from my problem; I'm trying to use two layouts interchangeably.

Yesterday I added Spanish to the keyboard layouts in the Gnome settings, and set it up so that 1) I could press the left Win-key to switch between English and Spanish, and 2) that the Num Lock and Scroll Lock LEDs would come on when I was using the Spanish layout (so I wouldn't have to start typing in order to figure out which was active). English was set to the "default" layout.

Whenever I login, it gives me this error:

Error activating XKB configuration.
It can happen under various circumstances:
- a bug in libxklavier library
- a bug in X server (xkbcomp, xmodmap utilities)
- X server with incompatible libxkbfile implementation

X server version data:
The X.Org Foundation
60802000

If you report this situation as a bug, please include:
- The result of xprop -root | grep XKB
- The result of gconftool-2 -R /desktop/gnome/peripherals/keyboard/kbd

In addition, it won't switch into Spanish, and the LEDs stay permanently on. Only after I go to Gnome, reset to the default settings, and then re-add the Spanish layout, Alt, and LED options does it work normally again. But then it goes back to not working the next time I login.
After I removed the English layout altogether and set the default to Spanish (both in Gnome and xorg.conf) I still get the error, though since all the keys work it doesn't really bother me. However, with Spanish as the system default, when I then add the English layout, once I press Alt to switch to English suddenly Spanish doesn't work anymore.

I'm thinking there has to be something with X that I'm not understanding here, since it's all fine until I log out and log back in.

I know this seems to be a common problem, and feel free to yell at me for repeating it when it's already been solved many times, but I thought since I'm trying to use the layouts interchangeably and not simply switch from one to another it might be a different solution.