reverse mapping checking getaddrinfo failed - POSSIBLE BREAK-IN ATTEMPT!

Weird problem has just developed.I was trying to port tunnel via relay through an intermediate ssh server. I have to do this because I got tired of script kiddie attacks filling my secure.log so I use port ≠ 22 at home. But my employer's preventers of information services block outbound traffic to destination ports other than the well known ports (and some well known ports too). So I have to ssh to an intermediate server then from there I can ssh to home, like this:

from work:
 ssh -L10548:localhost:50548 intermediate.server.com
from intermediate server:
 ssh -p56789 -L50548:localhost:548 home.network.com

The ssh session sets up just fine and I have full shell access to home. But when I try to ⌘k to afp://localhost:10548 I get a pair of error messages in the shell that says:

channel 4: open failed: administratively prohibited: open failed
channel 5: open failed: administratively prohibited: open failed

(the channel numbers change but the message is the same)

This worked just fine as recently as maybe two weeks ago (the last time I did this) and had been working fine for years. I can't think of a darned thing that I may have done to anything to have changed anything.

On the machine at home to which I am trying to afp, it's /var/log/secure.log has some entries, that correspond to the time of my remote login (uses DSA key exchange), that read:

Sep 14 07:55:11 iMac sshd[614]: reverse mapping checking getaddrinfo for intermediateServerHostName [intermediate.Server.IP.address] failed - POSSIBLE BREAK-IN ATTEMPT!
Sep 14 07:55:20 iMac sshd[614]: Accepted publickey for jv from intermediate.Server.IP.address port 25553 ssh2

Again, the shell session is successful, that's how I retrieved this info out of secure.log. It's just the forward port tunnels that aren't working. Although, the nastygram is annoying...

I get the same reverse mapping nastygram when concatenating the two ssh commands without "-L" port forward tunnel option.

Not seeing this behavior when connecting from another machine on the same home network with no intermediate server.

I tried a lot of different things last night, so my memory is a little fuzzy now, but I think I was successful with tunneled AFP mount when connecting from a home machine to another machine on the home network acting as an intermediate server. But when connecting from home machine to this (external) intermediate server then back into home network, I got the same nastygram and failure to ⌘k to afp://localhost:10548. At least I think that I seem to recall that that's what happened...

Looks like something to do with reverse mapping of something to this particular (and only one available to me and that I would trust) intermediate server but not exactly sure what it all means or how to fix it. So, does anyone have a clue what might be going on that would be allowing me to have a full access shell session but unable to tunnel ports all of a sudden? What is this reverse mapping nastygram? Is there something like a known_hosts file that I could delete? (I already took out all my .ssh/known_hosts files at the remote client, intermediate server and home ssh server, that didn't help).

Thanks