As far as music files goes ...... I don't use Amarok so cannot really comment ....... but I do use VLC, and have just used VLC to play between the two PCs here.
I have a Music partition shared out on PC1, and that share mounted in PC2.
I opened VLC on PC2, choose to open a directory from within the mounted share partition, and VLC is presently playing the files from that directory.
It is doing so in a 'streaming' fashion ...... in that it 'sucks' a bit from the file, plays it and then gets some more .............. it does not just load the whole file and play it, as I have seen previously with some players.
I did nothing special at all with the shares.
I would have most of the VLC plugins installed.
Sorry I cannot be any help with Amarok ....... maybe someone who uses it would have some better ideas.