Hi!
May there ara some duplicated item in your system and they are showing offline?
You have two alternatives:
Replace teh sylink.xml, you can find the tool and the documentation below:
https://www-secure.symantec.com/connect/downloads/sylinkreplacer-tool-connecting-sep-clients-sepm
for the new version of the tool ask from the symantec support.
If you have duplicated items in your database and one of them show offline:
http://www.symantec.com/business/support/index?page=content&id=TECH163349
Good Luck!