rdesktop sound problem

Hi,
I'm using rdesktop v1.7.0 to connect to a windows server 2008 SP2.
To connect, I use "-r sound: local" command line option.
When I connect the audio works fine, but after a some time sound is
disappears. To the sound came again, have to restart the rdesktop.
Can you help me with this problem?
Thanks in advance!

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