Backup Screen Does Not Appear for 1 Course - Moodle 2.4.1

Moodle2.4.1 (Build: 20130114)

I am building a site in Moodle 2.4.1 and have completed most of 5 courses.  Today I attempted to backup the Front Page and all the courses (through the backup option under Adminstration > Backup).  All backups worked but for one of the courses.  For that course, when I click backup a blank screen appears and nothing else happens.  Has anyone experienced this before?    Any suggestions on how to deal this problem?

Thanks for your time.

Dan