Trouble Importing

[wmharrison]

when i import a cdg and then hit the add to write disc, only about 4 songs
will appear on the write list. when i try to add the missing ones from my
songs i get an error message that says that the track file is missing. it also says that the file may have been renamed or is on a usb harddrive that is not plugged in.
why are some there and able to be used and some not?
is there anything i can do to fix this? they should all be going to the same
place.

any help would be helpful
thanks
wmharrison