Error using GtkColorChooser

[coloursofnoise]

Windows 7, Julia 1.5.0 also reproduced on Windows 10

trying to open a GtkColorChooser using either the following code

chooser = ccall((:gtk_color_chooser_dialog_new, Gtk.libgtk), Ptr{GObject}, (Cstring, Ptr{GObject}), "pick color", GtkNullContainer())
ccall((:gtk_dialog_run, Gtk.libgtk), Cint, (Ptr{GtkDialog},), chooser)

or with a GtkColorButton opens two error dialogs stating

There was a problem starting 
C:\Users\user\JULIA~1\ARTIFA~1\2D50DA~1\bin\LIBGIO~1.DLL
		
The specified module could not be found.

The GtkColorChooser still opens despite the errors