IPhone won't communicate via Remote, Snatch, Things and so on

Question

I have a very odd problem that I'm desperate to get to the bottom of.
I have an iPhone (2.1), a WiFi network, a MacBook Air (MBA) and a Mac Pro (MP).
I have recently installed several programs that open a channnel of communication between the iPhone and other computers on the wireless network. For example: Apple Remote ([http://www.apple.com/itunes/remote>), Snatch ([http://hoofien.com/Home.html]) and Things ([http://www.culturedcode.com/things>).
In all these applications, I can get the iPhone to communicate with the MBA without any problems. The iPhone appears as a remote in iTunes on the MBA as you'd expect, and controls iTunes correctly. Snatch on the iPhone detects the MBA and allows me to control the cursor. Things on the MBA finds the iPhone immediately, and synchronises tasks fine.
However, on the MP, I have no success at all. The iPhone does appear as a remote in iTunes, but won't find the library ([http://discussions.apple.com/thread.jspa?messageID=7988177]). The MP doesn't appear as a server when I open Snatch on the iPhone. Things on the MP can't find the iPhone at all.
There's clearly something going wrong on the MP that's preventing a certain kind of connection, but what might it be? Do these programs run over Bounjour, or another protocol? What can I check?
Just to confirm, both machines are running Leopard, and both are connected to the same wireless network via the same router. The MP has an Ethernet connection and the MBA uses WiFi, but even if I connect the MBA via Ethernet I have exactly the same problem (ie, the MBA works, the MP doesn't). Both machines are configured in a very similar way and there's nothing "obvious" that I can think of that would be preventing connections; there's no firewall running or anything like that.
Short of a complete re-install of the OS, which I'd rather not have to do, is there anything I can try that might fix this?!
UPDATE: I have now got Things to work, it seems that this was an unrelated issue. However, the problem remains with both Apple Remote and Snatch. Any ideas?
Message was edited by: chrisgibson.com

Answer 1

Just a quick follow up to this, in case anyone is having the same problem and stumbles across this post.
I recently purchased a Mac Mini to act as a media server. I connected the Mini to my wireless network, started iTunes, and then launched Remote on my iPhone. I was then able to control iTunes without any problems.
However. I found the wireless connection a bit slow, especially when streaming HD video from my Mac Pro. So, I bought a couple of ZyXel Powerline plugs -- these broadcast your Ethernet connection over the mains ring at about 200mbps. When I disabled the Mini's wireless connection and plugged it into the Powerline Ethernet port, everything worked really well and video streaming no longer skipped... but guess what? Remote on my iPhone no longer worked.
When I renabled the wireless connection on the Mini, Remote worked as expected. So, in conclusion, Remote only works when my target machine is connected to my network wirelessly.
It's the same network, running over the same ADSL wireless router, so I have no idea why this would be the case.
Is my router knackered? Everything else seems to work well over the wired connection, I can still share drives and so on. Are some ports closed on the wired network but not the wireless one? I certainly haven't deliberately configured anything this way, and I'm not sure it's even possible.
Very odd indeed. Still, I hope that this information is of some use to anyone else who is having similar problems.