avconv 64bit not installed

[simoncn]

You need to put the converter program (avconv or ffmpeg) in the opt/bin directory (see this section).

To help me understand your other issue, please produce a log file by doing the following:

1) Start MinimServer
2) From the minim icon, select 'Show log'
3) In the log window, set the logging level to Debug
4) Leave the log window open
5) Play a track using BubbleUPnP Server and the internal flac:wav converter until playback stops
6) In the log window, click 'Save as' to save a log file
7) Zip the log file (this step is important) and attach the zipped log file to a post here
8) In the log window, set the logging level back to Info

I will look at the log file and let you know what I find.