I've obtained gnome-applets_2.30.0.orig.tar.gz and
gnome-applets_2.30.0-0ubuntu2.diff which I think are 10.04's. The
original code is as above when I opened the bug although the line
numbers are slightly different. The diff doesn't change them in any
way. 12_modem_applet_waitpid_fix.patch still applies OK with an offset
of -15 lines.
So the problem remains in the code. My concern over the patch remains,
detailed in #3 above. waitpid() is clearly being wrongly used. That
can be fixed without further test results. Then the underlying problem
may come to light once the code processes waitpid's response properly.