Signed Applications not runing on Windows Vista XP and Server 2008

[pdduser]

 We signed our installer using the new Digital Certificate issued.

After Signing, Installer is not working on Most of the Vista, XP and Windows Server 2008 Machines after signing when downloaded from our website. I have copied the URLs of Signed and Unsigned Installers below.

 [Unsigned Installer]
 http://www.pddhost.com/vj/pen-drive-data-recovery-get-it-free.exe

 [Signed Installer]
 http://www.pddhost.com/vj/1/pen-drive-data-recovery-get-it-free.exe

 Please help!