Exchange GRT against Exchange 2007, worked on v12.5 but not 2010 R3

I recently upgraded a customer backup exec server to v2010 R3 with all SP and hotfixes installed.  Exchange 2007 GRT backup used to work on v12.5 but now fails with this message:

V-79-57344-918 - Unable to complete the operation for the selected resource using the specified options.  The following error was returned when opening the Exchange Database file:  '-546 The log file sector size does not match the sector size of the current volumn. '

If I turn off GRT, it works just fine.  But obviously I want to use the GRT option because the customer sometimes need to recover single mail messages.  I tried this fix but didn't work, http://www.symantec.com/business/support/index?page=content&id=TECH164166

thanks in advance