When you did the copy/paste to the external, you're placed music in a new location that iTunes knows nothing about. If you go through your iTunes library, you should see a bunch of songs with exclaimation points next to them. That means iTunes doesn't know where they are. You moved them, iTunes thinks they're in the old location. If there aren't any, try playing a song that you know you moved via copy/paste (and then deleted). I take it that once you copied to the external HD, you deleted them off of the C drive. iTunes will try to play it, but can't because it can't find it.
What you should have done after you changed the iTunes music location but before you deleted from your C drive, is consolidate your library. In iTunes go to the file menu, then library, then consolidate library. This copies all of your music that is in the old location to the new location (your external).
There are several ways to fix this. Probably the easiest thing is to delete everything in your iTunes library within iTunes, but (this is the important part) keep your files. (You're not sending them to the recycle bin).
When you delete something, you'll be asked 2 questions: "Are you sure you want to delete the selected song from the iTunes library?" (click on "remove") and "do you want to remove the selected song to the recycle bin or keep in your iTunes music folder?" (select keep file).
Keep iTunes open and then open up the folder on your external where your songs are kept. Start dragging and dropping from the folder on your external to the iTunes library (left side of iTunes where it says "library") What you're doing is telling iTunes where your music is. You could do this without doing the delete procedure, but you might end up with a lot of duplicates. If it's really only 100 songs, then that might not be a problem. But I suspect it might be more -- it's just that your playlists that you're transferring over to your Nano don't involve the rest of your library.
You'll probably need to rebuild your playlists after doing this.
You could just fix the songs that didn't get transferred over. Find out which ones. You could compare your playlist on iTunes with the playlist on the Nano. Go through your library in iTunes and look at any song that has an exclaimation point next to it. Double click on it and you'll get the message "the (title of song) cannot be used because the original file cannot be found. Would you like to locate it?" Click on locate and a windows explorer box should open up. Navigate to where you know the song resides and select it. You're now telling iTunes this is where the song is. Do that for each song you have a problem with.
Hope this helps. Good luck.
iTunes Error Message:
I just started getting the following error message from iTunes when trying to sync with my iPod Nano 4th (8GB) Generation:
?Some of the items in the iTunes library, including [name of piece], were not copied to the iPod [iPod name] because they could not be found.? The message went on to indicate ?100 total problems.?
Being new to iPod and iTunes - this is how I copied CDs into iTunes:
1. I opened iTunes on my Dell Vostro 420 desktop computer (Vista Business OS).
2. I created a series of standard Playlists and Playlist Folders in the Library (left side of the screen). Here?s typical entry with sub-directories:
[Main Playlist Folder] ENGLISH MUSIC
[Playlist Folder Sub-Dir] +ENG-CLA-ALL*
[Playlist Folder Sub-Dir] COATES, ERIC
[Playlist Sub-Dir?s] London Suites.
Music of Eric Coates I & II.
? and so on.
* means English-Classical-All (as opposed to) ENG-POP-ALL (for pop music)
3. I inserted CD in computer CD-ROM drive.
4. I waited for prompt from iTunes to start uploading. Did so.
5. On completion, I scrolled down Library screen and opened ?Recently Added.?
6. I found and selected selections and did ?Add to Playlist? to where it wanted them.
Now I sometimes had to transfer music files from a straight playlist to a folder with its own playlists. I used the same ?Add to Playlist? function and it seemed to work.
Brief Background: - Being new to iPods, iTunes, etc, I first installed iTunes on my C: drive. When I soon ran out of disk space, I created a new iTunes directory, etc. on an external HD.
In iTunes itself, I clicked on the Advanced tab and changed the ?iTunes Music Folder Location? to the new location. Finally, I did a straight file copy/paste of my iTunes Music files from the C: drive to the external HD. Newly uploaded CDs soon when directly to the new location.
To date I?ve uploaded 26.1 GB (2778 files in 402 folders to iTunes. I specialize in the classical genre but include some movie soundtracks and some pop, so most of my ?songs? are on the long side.
Every so often, I select portions of the library ? i.e. ?English Music? -- to sync to my iPod. And here is where the aforementioned error message starting to appear just recently.
BTW ? in certain albums some tracks sync OK while others don?t. ??
So -- where have I gone wrong ? and how can I sync to my iPod effectively without this annoying error message?
Many thanks.

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