I'm seeing this same problem as well. Looking at the debug output, the encoder does not seem to even be considering the "lame" element as a possibility. There are two possible reasons for this; either the profile's pipeline does not launch (I've verified that it does on my system with gst-launch) or the code can't find the encoder element in the pipeline. I'm investigating further to see if I can determine which of the two tests is failing.
I'm seeing this same problem as well. Looking at the debug output, the encoder does not seem to even be considering the "lame" element as a possibility. There are two possible reasons for this; either the profile's pipeline does not launch (I've verified that it does on my system with gst-launch) or the code can't find the encoder element in the pipeline. I'm investigating further to see if I can determine which of the two tests is failing.