Restoring a FrontBase database
Is the mac and Windows machines running same version of FrontBase? if not you have to export the database to file format and import it: 

On mac :

WRITE ALL OUTPUT(DIR = '&lt;path&gt;', TYPE = 'FrontBase',
CONTENT = TRUE);


On Windows:

script &lt;path&gt;/schema.sql;


See more in release note: http://www.frontbase.com/cgi-bin/WebObjects/FBWebSite