This behavior was observed in both 0.8.5 and .6test1, with DVD, M4P, and XviD files.
I'm running VLC on an IBM Thinkpad R31 laptop with Windows XP SP1.
If I start VLC with the AC connected, it plays for a couple of seconds then freezes. If I then disconnect the power, it unfreezes and plays normally. If I reconnect, it freezes again, and so on.
Here is what appeared in the message window in the 10 seconds or so after AC was connected while an M4P file was playing:
main debug: audio output is starving (4700767), playing silence
main warning: received buffer in the future (5099299)
main warning: received buffer in the future (5122066)
main warning: received buffer in the future (5144857)
main warning: received buffer in the future (5167676)
main warning: received buffer in the future (5090701)
main warning: received buffer in the future (5113262)
main warning: received buffer in the future (5135809)
main warning: received buffer in the future (5158330)
main warning: received buffer in the future (5180920)
main warning: received buffer in the future (5106517)
main warning: received buffer in the future (5129070)
main warning: received buffer in the future (5151656)
main warning: received buffer in the future (5174231)