It can fsck the root partition fine -- just like all other Linux installations on the planet! So nothing special there.

The reason I believe it is running out of memory -- actually it's probably running out of page frames -- is because the player software locks itself into memory, refusing to be paged out. This creates considerable pressure on physcial ram (aka. page frames), so much that fsck is unable to allocate the chunks that it requires to do its job. Maybe the player is neglecting to free() the music buffer space it normally nabs on startup?

Anyway, as observed, without a player running, fsck works just fine -- maybe even without the need for swap, though I haven't tested that.

Cheers