Looks like a
bug in bash-completion. The variable character ($) seems to be escaped instead of being replaced with the proper value (I can't confirm this on my system because I'm at work riht now using Windows). Unfortunately there's no information in this bug report as to how to workaround it. Maybe downgrading bash-completion, to the version before the one you're using, if apt-get/aptitude lets you do that? You could also join the bug report and see if it gets fixed for the next version.
Regards.