In general the problem happens when I'm running gnome-terminal. However I alsso found the same problem when running evolution.
Hmm...strange. This seems like either the accessibility or audio infrastructure might be going bad. :-( If you end up seeing a pattern, please let us know.
About update to Ubuntu Intrepid release I can do but I need some help.How can I update? Do I need to grab another cd or I can update using some command in Ubuntu?
Keep in mind that Intreprid is still under development and is bleeding edge stuff. So, as I say, you might end up bleeding. :-) I've not tried an accessible install for Intrepid yet, but there are some notes for Hardy available here -- they might be very similar to Intrepid:
http://live.gnome.org/Orca/UbuntuHardy Will