Launch functions one after another

Question

I wrote a function that pastes in the currently selected color from the palette to the buffer:

(defun palette-paste-in-current-color ()
  (interactive)
  (cua-paste (palette-current-rgb-to-kill-ring)))

I wrote a function that calls the palette from the current content of the kill ring (RGB content):

(defun palette-launch-from-kill-ring ()
  (interactive)
  (palette (concat "#" (substring-no-properties (car kill-ring)))))

I thought it would be handy to just move the point to an rgb color in a buffer, then use expand-region followed by cua-copy-region to automate the process. So I wrote:

(defun palette-launch-from-kill-ring ()
  (interactive)
  (er/expand-region)
  (cua-copy-region)
  (palette (concat "#" (substring-no-properties (car kill-ring)))))

But I get an error and I am puzzled on how to run these functions one after another successfully.

EDIT:

The error I get is (can't decipher what is going on here):

apply: Wrong number of arguments: #[(ad--addoit-function arg) "Ä        Å 
!)" [ad-return-value rectangular-region-mode ad--addoit-function arg nil rrm/switch-to-multiple-cursors] 3], 1