After some searching, this problem appears to be caused by a conflict with 'acroread'. In 'acroread.sh' there is a function '_filedir()' which seems to override the default '_filedir()'.
Try uninstalling acroread and reinstalling from the repos. The version of Adobe Reader in the repo appears to be ok (there is an 'if' statement guarding the definition of the '_filedir()' function.
After some searching, this problem appears to be caused by a conflict with 'acroread'. In 'acroread.sh' there is a function '_filedir()' which seems to override the default '_filedir()'.
Try uninstalling acroread and reinstalling from the repos. The version of Adobe Reader in the repo appears to be ok (there is an 'if' statement guarding the definition of the '_filedir()' function.