mythfrontend.real crashed with SIGSEGV in memcpy()

Binary package hint: mythtv

Attempted to use MythPhone to call another computer on the lan (also using MythPhone; both computers use the same current Hardy MythTV packages).
Almost immediately after the call was connected, the frontend process died. The receiving computer's frontend kept running as if the caller was still connected.

Neither computer is set to register to a SIP server
Both computers' microphone device is set to /dev/dsp
Both computers' Webcam device is set to /dev/video0 with transmit and capture resolution set to 352x288, 30fps, 400Kbps.
The sender's webcam is a Z-Star Microelectronics Corp ZC0303 WebCam 0ac8:303b (vender is Vimicro) using the gspca.ko module (zc0301.ko is not correct for this device despite the similar name)
The receiver's webcam is the Virtual Video Device (vivi.ko) since it lacks a real webcam
Both devices function without incident using other applications (e.g., Ekiga)

ProblemType: Crash
Architecture: amd64
Date: Tue Feb 12 10:58:18 2008
DistroRelease: Ubuntu 8.04
ExecutablePath: /usr/bin/mythfrontend.real
NonfreeKernelModules: nvidia ath_hal
Package: mythtv-frontend 0.20.99+trunk15849-0ubuntu2
PackageArchitecture: amd64
ProcCmdline: /usr/bin/mythfrontend.real --logfile /var/log/mythtv/mythfrontend.log
ProcCwd: /home/genecide
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Signal: 11
SourcePackage: mythtv
StacktraceTop:
 memcpy () from /lib/libc.so.6
 PhoneUIBox::TransmitLocalWebcamImage ()
 PhoneUIBox::customEvent ()
 QObject::event () from /usr/lib/libqt-mt.so.3
 QWidget::event () from /usr/lib/libqt-mt.so.3
Title: mythfrontend.real crashed with SIGSEGV in memcpy()
Uname: Linux mythtv-livingroom 2.6.24-7-generic #1 SMP Thu Feb 7 00:56:31 UTC 2008 x86_64 GNU/Linux
UserGroups: adm admin audio cdrom dialout dip floppy lpadmin mythtv netdev plugdev powerdev sambashare scanner video