The _filedir() function in acroread's (at least Linux) bash completion file conflicts with the one from the bash completion project, http://bash-completion.alioth.debian.org/ - the one in acroread ends up overriding the one in the latter with an implementation that is not compatible/does not meet expectations of various completions from the bash completion project, thus breaking them in subtle, hard to debug ways.
Please consider renaming the _filedir bash function shipped in acroread's bash completion file to for example _adobe_filedir (or inlining it in _acroread) to resolve the issue.
I just installed Adobe Reader 9.4.7 on my Ubuntu 12.04 Beta system, and hit this bug. I had no idea why filename completion was suddenly broken until I did some searching and turned up https://bugs.launchpad.net/ubuntu/+source/acroread/+bug/769866/comment s/7 . So, the bug is still there, over a year later.
Adobe, please fix this, or else get rid of acroread.sh . It's much worse breaking filename completion than whatever bit of extra functionality it might be providing to acroread users (most users won't run it from the command line in any case).
Thank you for reporting the issue , we are now tracking this internally through a bug and hope to fix this in future updates. However , till then you may use the workaround #10 as suggested in the link https://bugs.launchpad.net/ubuntu/source/acroread/bug/769866/comments/10 . This looks specific to 11.04 and now to 12.04 Beta as well.