For Dialogic Drivers you should be able to contact the company where you purchased the Dialogic Card from and have them give you the latest system release to install. Here is a link to Dialogic's system release page:
http://www.dialogic.com/support/helpweb/dxall/systemrelease.htm
They have complimentary download of the older SR5.1.1:
http://resource.dialogic.com/telecom/support/releases/winnt/Sr511/index.htm
Please note that SR5.1.1 will not work with the latest Dialogic Cards e.g. it will not work with the D/4PCIU.
