Unable to get (menu-entries (...)) to work properly

[dian_cecht]

So I'm trying to define a new menu-entry for my desktop system using
GuixSD's system config. I've ran into an interesting problem that I'm
not sure how to resolve. Forgive any formatting issues here, I'm having
to hand-copy this over from a VM I'm using to test everything. I know
it's this piece of code that is acting up since this is a recent
addition to an already working config. Replacing the actual
(menu-entry ...) with '() doesn't cause any errors, fwiw.

(bootloader (grub-configuration (device "/dev/sda")
                                (menu-entries
                                 (menu-entry
                                  (label "Desktop")
                                  (linux "/boot/kernel")
                                  (linux-arguments "")
                                  (initrd "/boot/initramfs")))))

This constantly throws errors that I can't sort out. Attached (if I do
it properly with this new email client) is a screenshot of the error.

2017-04-09-003333_720x400_scrot.png
Description: PNG image