When LiveUpdate is used to Upgrade the Netbackup client version, you might be seeing issues that LiveUpdate is failing with the message:
"20.06.2013, 12:25:58 GMT -> HttpSendRequest (status 304): Request succeeded - File up to date so download is not required" in log.liveupdate or in the NetBackup job details you also can find the information "No Updates found".
This problematic you can only find when the Upgrade to the version 184.108.40.206 was done with LiveUpdate. LiveUpdate always downloads newer files than this what it has already in its local cache directory: f.e. "C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads"
When the LiveUpdate prepares to download f.e. symantec$20netbackup$20x86$20windows_7.1_english_livetri.zip the files is always checks for the time stamp and when this file is already present in the local cache with a newer modification date, than LiveUpdate wont download this file.
As Netbackup 7.5 was released erlier than the Netbackup 220.127.116.11 its LU files has as well the older time stamp.