My music files are located on a QNAP nas. While I can mount them and see the SMB share in Ubuntu Unity, I can not access the shares in the "add library" within gmb. I tried SMB://xxxx, no luck. Any tips? Thanks.

Sorry this is not supported currently, you have to mount the SMB share so that it behaves exactly as a local folder.
Also currently most mp3 will be read completely the first time they are added to determine their length reliably, it will be deactivable in the future but it the mean time it makes adding non-local mp3 files much slower.