Edit Mail Aliases: Error - Perl execution failed

After adding an alias to a domain in the "Edit Mail Aliases" section, and clicking save, I get the following error. However, it looks like the changes stick after the save.

Error - Perl execution failed

Undefined subroutine &WebminCore::fstype_name called at /usr/libexec/webmin/mount/log_parser.pl line 16.

Status: 
Closed (fixed)