The error:
PHP Fatal error: Maximum execution time of 30 seconds exceeded in gallery/modules/exif/lib/exifer/makers/olympus.inc on line 81
The reason:
The exif have been updates with Gallery2, but the libery have not been updated.
The solution:
Download the newest file for olympus images here:
http://www.zenphoto.org/trac/browser/trunk/zp-core/exif/makers/olympus.php
Replace the "olympus.inc" with the new file, and everything works.
Source for solution:
Gallery2 forum