Compressor hangs/freezes at Blu Ray burn stage

Having editied my HD video in FCP X, and then Share -> Send to Compressor, I added markers manually in the Compressor Timeline, set the Job Action as "Create Blu-Ray disc", and then Submit. I have a Blu-Ray burner in the second optical disc space in my Mac Pro which I set as the output device.

What happens is this: Compressor successfully creates the .264 video file and the .ac3 file on the desktop. The progress bar then stops, it says time remaining is just over 7 minutes, and that's it. Disc isn't burnt and Compressor hangs at that point.

Same happens if I set the output device to be the hard disk (i.e. create a BDMV folder).

Someone may be able to make sense of the end of the Share Monitor log file:

Stream Type: H.264 BD-compatible Video Elementary

Frame Dimensions: 1920x1080

Frame Rate: 25.000000 interlaced (top field first)

Aspect Ratio: square-pixel

Video Format: Component / Rec. ITU-R BT.709

Rate Control: 1-pass VBR (30000000 bps target, 35000000 bps max)

Markers: { 0 4906 17627 34580 56150 80998 87953 109902 }"/>

<log tms="354763687.812" tmt="03/30/2012 12:28:07.812" pid="63713" msg="H264 Transcode, rendering in YUV 8 bit 422"/>

<log tms="354771687.743" tmt="03/30/2012 14:41:27.743" pid="63713" msg="Done _processRequest for job target: file://localhost/Users/sjt/Desktop/General%202011%20-%20Project-H.264%20for%20B lu-ray.264"/>

<mrk tms="354771688.623" tmt="03/30/2012 14:41:28.623" pid="63713" kind="end" what="service-request" req-id="30D161DF-0A23-4227-8FD6-23A35724A115:1" msg="Processing service request end."></mrk>

<mrk tms="354771688.797" tmt="03/30/2012 14:41:28.797" pid="63713" kind="begin" what="service-request" req-id="CE492796-43E6-4AC1-8C95-9A2289D9961E:1" msg="Processing."></mrk>

<log tms="354771688.816" tmt="03/30/2012 14:41:28.816" pid="63713" msg="starting _processRequest for job target: file://localhost/Users/sjt/Desktop/General%202011%20-%20Project-Dolby%20Digital %20Professional.ac3"/>

<log tms="354771993.498" tmt="03/30/2012 14:46:33.498" pid="63713" msg="Done _processRequest for job target: file://localhost/Users/sjt/Desktop/General%202011%20-%20Project-Dolby%20Digital %20Professional.ac3"/>

<mrk tms="354771993.528" tmt="03/30/2012 14:46:33.528" pid="63713" kind="end" what="service-request" req-id="CE492796-43E6-4AC1-8C95-9A2289D9961E:1" msg="Processing service request end."></mrk>

</logs>

</service>

<service hostName="SJT-Mac-Pro.local" displayName="Simon's Mac Pro" type="requestprocessor:com.apple.qmaster.contentcontroller" address="tcp://10.1.1.100:53080">

<logs tms="354778947.412" tmt="03/30/2012 16:42:27.412" pnm="unknown">

<log tms="354778947.412" tmt="03/30/2012 16:42:27.412" pid="63711" kind="mrk" sub="error" what="get-log" avail="false" msg="Service is down."/>

</logs>

</service>

</services>

Thanks in advance.

Simon