Trickle fails to load firefox.

I'm not quite sure how to diagnose where this error is happening.

I want to use trickle in order to try and limit the download speed that firefox uses so that I can download files without maxing out the bandwidth of our shared connection.

I do this by using:

trickle -d 300 firefox

and also tried using the direct link to the binary:

trickle -d 300 /usr/lib/firefox-3.5.7/firefox-3.5

In the second case, ldd showed that it should have the necessary libraries...

I am using Ubuntu 9.10, updated fully, on a 64-bit core i7 computer.

When I try trickle -d 300 gnome-terminal, the terminal opens immediately and trickle returns, so it's something about firefox that is preventing it from working.

Running trickle in verbose (-vvvvv) mode just returns with no information for the second direct binary call, while it returns with "firefox: [trickle] Initialized" when I try running the first indirect call through /usr/bin/firefox.

I'm very confused.

Is there another way to get bandwidth limiting in firefox? This is such a glaringly annoying missing feature...