as reported by Tobias Ljunggren on the f-spot ml:

I've been trying to get 0.6 up and running for a while but I always have
problems with the color management. From debug output:
[Info  08:16:44.108] Hack for gnome-settings-daemon engaged
Exception in Gtk# callback delegate
  Note: Applications can use GLib.ExceptionManager.UnhandledException to
handle the exception.
System.ArgumentNullException: Argument cannot be null.
Parameter name: key
  at
System.Collections.Generic.Dictionary`2[System.String,Cms.Profile].ContainsKey
(System.String key) [0x00000]
  at FSpot.ColorManagement.AddProfiles (System.String path,
IDictionary`2 profs) [0x0002c] in
/home/tolj/source/f-spot/src/Core/ColorManagement.cs:63
  at FSpot.ColorManagement.get_Profiles () [0x0008d] in
/home/tolj/source/f-spot/src/Core/ColorManagement.cs:37
  at FSpot.TagSelectionWidget.IconDataFunc (Gtk.TreeViewColumn column,
Gtk.CellRenderer renderer, TreeModel model, TreeIter iter) [0x0003f] in
/home/tolj/source/f-spot/src/TagSelectionWidget.cs:190
  at GtkSharp.TreeCellDataFuncWrapper.NativeCallback (IntPtr
tree_column, IntPtr cell, IntPtr tree_model, IntPtr iter, IntPtr data)
[0x00000] in
/usr/src/packages/BUILD/gtk-sharp-2.12.9/gtk/generated/GtkSharp.TreeCellDataFuncNative.cs:57

   at GLib.ExceptionManager.RaiseUnhandledException(System.Exception e,
Boolean is_terminal) in
/usr/src/packages/BUILD/gtk-sharp-2.12.9/glib/ExceptionManager.cs:line 58
   at GtkSharp.TreeCellDataFuncWrapper.NativeCallback(IntPtr
tree_column, IntPtr cell, IntPtr tree_model, IntPtr iter, IntPtr data)
in
/usr/src/packages/BUILD/gtk-sharp-2.12.9/gtk/generated/GtkSharp.TreeCellDataFuncNative.cs:line
61
   at Gtk.Application.gtk_main()
   at Gtk.Application.Run() in
/usr/src/packages/BUILD/gtk-sharp-2.12.9/gtk/generated/AboutDialog.cs:line 1
   at FSpot.Driver.Main(System.String[] args) in
/home/tolj/source/f-spot/src/main.cs:line 345
[Debug 08:16:44.747] Finalizer called on FSpot.PhotoView. Should be Disposed

Regardless of what I set at
/apps/f-spot/ui/color_management_display_profile and
/apps/f-spot/ui/color_management_output_profile I get the same error.
Managed to get it up an running once (I think I entered sRGB.icc from
gconf-editor), selected color profiles from the list in preferences but
since then it seems impossible to f-spot up and running...