gthumb version :2.10.9 
os:Sloaris
steps:
start gthumb
select the item  "Write to CD" in File menu
select "Current Folder" in Write to CD dialog
click "OK"

then an error dialog pops up saying"Could not move the items: Invalid parameters"
I have made some tests to explore the reason of this bug.
The test:
modify the function: static void ok_clicked_cb (GtkWidget  *widget,DialogData *data) in dlg-write-to-cd.c. 
In this function at the 126th line is  
   126  char *dest_folder = build_uri ("burn:///", file_name_from_path (
data->current_folder), NULL);
   127	        dlg_folder_copy (GTH_WINDOW (data->browser),

I suspected that maybe there's something wrong with the path"burn:///".So I inserted this sentence after line 126
   	        dest_folder = strdup("file:///export/home/laixin/1");
In this way after remaking gthumb it was successful to copy the source folder to the dest folder ,file:///export/home/laixin/1.

In the end ,I drew the conclusion that there must be something different between common folders and CD/DVD Creator Folder.

That's all of what I have got