All torrents stalled

[DulcetAirman]

I use version "Transmission 1.22 (6191)" on my Popcorn Hour (Networked Media Tank).
It used to download all torrents that I added but now everything is stalled. I removed some torrents to see it that was the problem (some were very big). But that didn't help.
Starting them doesn't help since they are only stalled, not stopped. Is there a way to force start them as you can do on other clients?
Port forwarding is correct as I can see that there are other hosts sending packets to that port.
How do I debug? Can I start transmission so it writes to a log file?

[DulcetAirman]

I just removed another big torrent and now two other torrents started. Looks like transmission cant handle torrents of 40GB.

[livings124]

Current version is 1.75. Your version is not supported.

[jneusteter]

I had somewhat the same problem:

My fix:
My router assigns port forwarding to a per physical ethernet plug basis. If you change the cables around after setting up all the port forwarding and other firewall settings, you have to reset all the settings to the new way you plugged in all your ethernet cables. I went into my router and deleted all settings and totally reconfigured it to my new set up.

Hope it helps.