undefined function exif_read_data()

Hi,
interestingly, after running the module with no trouble on my dev box, I'm experiencing a problem on the development box.

When running cron.php, I get this:
Fatal error: Call to undefined function exif_read_data() in /home/miclos/public_html/sites/all/modules/fast_gallery/fast_gallery.inc on line 56

This function doesn't exist in either fast_gallery.module or fast_gallery.inc. Curious how it doesn't occur on my local box.

Any suggestions?

P.S. Thanks for the module. It looks good...