Currently Being ModeratedSep 13, 2012 7:41 PM (in response to pvolker)
Undo what you did with the preferences changes.
iTunes: How to move [or copy] your music to a new computer [or another drive] - http://support.apple.com/kb/HT4527
Quick answer if you use iTunes' default preferences settings: Copy the entire iTunes folder (and in doing so all its subfolders and files) intact to the other drive. Open iTunes and immediately hold down the Option (alt) key (shift on Windows), then guide it to the new location of the library.
Do not confuse moving your whole folder and library with moving just media files as in (this is what you did with changing preferences)
iTunes for Mac: Moving your iTunes Media folder - http://support.apple.com/kb/HT1449