Microsoft does not support the use of FAT file systems or FAT32 file systems with Internet Information Services.
The following GFI products require Internet Information Services, thus making it impossible to install these products on a FAT/FAT32 file system:
- GFI MailEssentials
- GFI MailSecurity
- GFI MailArchiver
- GFI FAXmaker 12 and higher
Further information can be found at: http://support.microsoft.com/kb/907733