7.6.4_1039 is the initial release of the NW 7.6.4 SW (7.6.4.0). The current 
release is 7.6.4.5_1088, available from the "Cumulative hotfix" download 
location.
So installing this version should do the job.

Unfortunately, EMC does not support the the 4th digit right now.
An update from 7.6.3.x to 7.6.4.x will work. You will recognize when the 
"NetWorker Update" window will appear.
However, to update for example from 7.6.4.2 to 7.6.4.3 you must deinstall the 
old version first. Do NOT delete the databases, just install the new version.

Currently, EMC does not indicate the build number. If you are in doubt, install 
the NW CLIENT SW on another machine. It will not take long.
Then run the following command sequence:

E:\nsr\bin>nsradmin -p nsrexec
NetWorker administration program.
Use the "help" command for help.
nsradmin>
nsradmin> . type: NSRLA
Current query set
nsradmin>
nsradmin> show "NetWorker version"
nsradmin>
nsradmin> p
           NetWorker version: 7.6.4.1.Build.1049;
nsradmin> q

E:\nsr\bin>

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