Great work with this contribution.
I too was suffering from blank froogle.txt files being written. I'm running IIS 6.0 on Windows Server 2003 x64 and after tweaking the permissions for my 'feeds' folder I was able to get everything working.
I have noticed two small errors with the contribution (nothing major), but I felt they should be reported.
1 - In admin>tools>google froogle feeder the link within this text, "NOTE: You may view your product feed file before proceeding to step 2.", does not take into account different feed directories (it just points to /feed/ regardless of the output directory configuration).
2 - The update_1_4_3.sql and googlefroogle.sql in the 1.4.3 release contain a small typo. 'UPC' has been listed in place of ISBN.
This then creates two options named 'UPC' in the configuration settings.
(NULL, 'UPC', 'GOOGLE_BASE_UPC', 'false', 'Include products UPC?', @configuration_group_id, 31, NOW(), NULL, 'zen_cfg_select_option(array(\'true\', \'false\'),'),
(NULL, 'UPC', 'GOOGLE_BASE_ISBN', 'false', 'Include products ISBN?', @configuration_group_id, 32, NOW(), NULL, 'zen_cfg_select_option(array(\'true\', \'false\'),');
I hope this helps. :)