I had a mini server that died and never used the server tools in the first place. Is the unlimited client serial key worth anything here or on the auction sites?
If this is a Mac mini server, the earliest ones came with 10.6 (Snow Leopard Server) and the distribution disks will only install on the Mac mini server model of that vintage. I believe I read a discussion of this at that time. (I've got one of those mini servers myself, but have since upgraded to Mavericks + Server.