Pulseaudio causes applications to hang

Binary package hint: pulseaudio

I've had several applications crash or hang recently, and there is usually unusual activity related to pulseautio either in top or in the log files when it happens. Example from this morning, when testing XBMC, it hung completely and gave no error messages in its application log, but the system messages show:

Aug 24 11:20:40 plasken pulseaudio[4423]: alsa-util.c: Device hw:1 doesn't support 44100 Hz, changed to 16000 Hz.
Aug 24 11:20:40 plasken pulseaudio[4423]: alsa-util.c: Device hw:1 doesn't support 2 channels, changed to 1.
Aug 24 11:20:40 plasken pulseaudio[4423]: module-alsa-source.c: Your kernel driver is broken: it reports a volume range from 18.00 dB to 18.00 dB which makes no sense.
Aug 24 11:35:56 plasken pulseaudio[5657]: main.c: Called SUID root and real-time and/or high-priority scheduling was requested in the configuration. However, we lack the necessary privileges:
Aug 24 11:35:56 plasken pulseaudio[5657]: main.c: We are not in group 'pulse-rt', PolicyKit refuse to grant us the requested privileges and we have no increase RLIMIT_NICE/RLIMIT_RTPRIO resource limits.
Aug 24 11:35:56 plasken pulseaudio[5657]: main.c: For enabling real-time/high-priority scheduling please acquire the appropriate PolicyKit privileges, or become a member of 'pulse-rt', or increase the RLIMIT_NICE/RLIMIT_RTPRIO resource limits for this user.
Aug 24 11:35:56 plasken pulseaudio[5660]: alsa-util.c: Device hw:1 doesn't support 44100 Hz, changed to 16000 Hz.
Aug 24 11:35:56 plasken pulseaudio[5660]: alsa-util.c: Device hw:1 doesn't support 2 channels, changed to 1.
Aug 24 11:35:56 plasken pulseaudio[5660]: module-alsa-source.c: Your kernel driver is broken: it reports a volume range from 18.00 dB to 18.00 dB which makes no sense.
Aug 24 11:37:10 plasken kernel: [ 1064.637988] hda-intel: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
Aug 24 11:37:30 plasken kernel: [ 1084.878264] 3:3:3: cannot get freq at ep 0x86
Aug 24 11:40:33 plasken pulseaudio[6701]: alsa-util.c: Device hw:1 doesn't support 44100 Hz, changed to 16000 Hz.
Aug 24 11:40:33 plasken pulseaudio[6701]: alsa-util.c: Device hw:1 doesn't support 2 channels, changed to 1.
Aug 24 11:40:33 plasken pulseaudio[6701]: module-alsa-source.c: Your kernel driver is broken: it reports a volume range from 18.00 dB to 18.00 dB which makes no sense.

I'm not sure if PulseAudio IS the culprit, but those messages indicate to me that something is wrong?

Thank you very much for your help in resolving this matter.

ProblemType: Bug
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: andersja 4600 F.... mixer_applet2
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xfa100000 irq 22'
   Mixer name : 'Realtek ALC883'
   Components : 'HDA:10ec0883,1458e601,00100002'
   Controls : 41
   Simple ctrls : 23
Card1.Amixer.info:
 Card hw:1 'U0x46d0x8c1'/'USB Device 0x46d:0x8c1 at usb-0000:00:1d.7-5, high speed'
   Mixer name : 'USB Mixer'
   Components : 'USB046d:08c1'
   Controls : 2
   Simple ctrls : 1
Card1.Amixer.values:
 Simple mixer control 'Mic',0
   Capabilities: cvolume cvolume-joined cswitch cswitch-joined
   Capture channels: Mono
   Limits: Capture 0 - 3072
   Mono: Capture 0 [0%] [18.00dB] [on]
DistroRelease: Ubuntu 9.04
NonfreeKernelModules: nvidia
Package: pulseaudio 1:0.9.14-0ubuntu20.2
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: pulseaudio
Uname: Linux 2.6.28-15-generic i686