Server Is Not Accessible from Outside the LAN

[Z-Man]

forwards it using 192.168.1.254:4534 to 192.168.1.2:4534, which is the Time Capsule. The Time Capsule then takes the ping from there and forwards it using 10.0.1.1:4534 to 10.0.1.3:4534, which is the computer running my server

Two potential problems there. First, those IPs are from different private subnets, some software (like firewalls, they'd treat anything incoming from a different subnet as external internet traffic) may get confused.
Secondly, why forward it twice? Can't the 'modem' (it has an IP, so I suspect it's already a router in its own right) forward to the server directly? Sounds like that could eliminate a potential problem source.
Edit: ah, Time Capsule acts as a bridge between your two private subnets, and your server happens to be on the 'inner' subnet with indirect internet access? I guess the setup should be OK then, but I'm afraid you'll need to whip out wireshark or some other network sniffer and find out where the packets get lost exactly.

And good job making a new thread about the other two issues. The warning message may be relevant to the issue here (emphasis on 'may', we'll see about it), but the reservation spam is definitely unrelated.

[TechnoCat]

Not sure about that. I thought the modem was the bridge and the Time Capsule handles all the routing functions. It should, anyway. I guess the modem's designed to be a router as well, but it can't create a wireless network, which is what I want (and need; the Ethernet port on this laptop is busted) so I just made sure when I got the modem that the Time Capsule stayed in charge of the main routing. But then the modem refused to be put into bridge mode from here, and I dunno what, so I just told it there was one computer (really the Time Capsule) . So it thinks there's one computer on DHCP or something. Anyway, it works for just about everything. And like I said, Back to My Mac works fine, so we know at least some port forwarding is going on.

[Z-Man]

Yeah, I imagine some cable modems operate in a mode where they give a single PC that's able to connect a single local IP. Anyway, this is really all beyond my expertise. All I can say is that something somewhere is not getting through and that I can't see any errors in the configuration.