Removing the IcedTea plugin using Synaptic allowed Firefox to open normally. I'll test whether reinstalling the plugin causes Firefox to crash and report here if it does.

I was also having the same problem but it disappear once I removed the icedtea plugin from synaptic. After that I tried to re install the icetea plugin again and there was no issue in firefox, it started normally.

My icetea6-plugin version is 6b20-1.9.1-1ubuntu3

I had the same problem and removed icedtea and then Firefox worked. I installed icedtea again and Firefox worked without any problems. My question is how did this get figured out? I would be interested in how someone knew this was the answer. Thanks.