On Ubuntu 14.04, in the System Logs module (error occurs in order modules that uses the input box), using the input box to navigate to the desired file - the choose file dialogue box generated the following error:
Error - Perl execution failed
Undefined subroutine &main::quote_javascript called at /usr/share/webmin/chooser.cgi line 189.
See attachment as well
Known issue, will be fixed in the next Webmin release.