bitcoin-qt 0.6.3 dumps core

[mores]

I am currently running ./bitcoin-0.6.3-linux/bin/32/bitcoin-qt on Ubuntu 12.04 LTS

After a random period of time I get:

Code:

bitcoin-qt: Fatal IO error: client killed
bitcoin-qt: /usr/include/boost/thread/pthread/mutex.hpp:50: void boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed.
Aborted (core dumped)

How can I prevent bitcoin from doing this ?