markl, the entries in /etc/fstab are similar to the mount command line, but not exactly the same. I think your entry in /etc/fstab should look like this:
//192.168.0.29/music /mnt/NAS cifs user=,password=,rw,iocharset=utf8,sec=ntlm 0 0
The space character is the separator in /etc/fstab so be sure that you have no spaces in the options section (the part that starts “user=…”).