Cannot delete login item "You cannot change this item because it's managed by your system administrator"

Question

We migrated a server (ldap and file serving) to some new machines, which have new names.  We've got all of the login and file sharing functionality working on the new machines, but wherever we have a mount of a share in the Login Items for a user, we can't get the old machine out of the Login Items.  It's not fatal, but it does make login take a lot longer because it has to fail first.
We can mount the share from the new server, and save THAT in a NEW Login Item just fine -- it's just that when you click on the old defunct one the minus sign is greyed out, and the mouseover says "You cannot change this item because it's managed by your system administrator."  There is a yellow triangle next to the item in the list.  Went into the user's ~/Library/Preferences/com.apple.loginitems.plist and it's not in the file.  The /Library/Preferences don't have anything that looks like a plist of the right name.
Where do I find it and how do I get rid of it?

Answer 1

In response to ManishBhatt94's post today, I may have some information that may be useful to you. I called Microsoft's 800-642-7676 and spoke with a technical representative with questions pertaining to my particular issue. I also have friend that has the
same issue with her computer running windows 8. A representative from my ISP told me how to go into 1)Tools, 2)Internet Options, 3)Connections, 4)LAN settings and uncheck the proxy settings box. However after restarting or shutting down my computer it reappears.
It will also reappears while I play games on Facebook not allowing me continue until I go back into the proxy settings in LAN and uncheck the box AGAIN and AGAIN. A local owner of a computer repair shop told my friend that it was a virus. After speaking with
Microsoft today I was told the same thing/it was more than likely a virus on my personal PC at home. As most people likely do,  I use wireless internet in my home on the affected computer. Solution; as suggested by Microsoft rep was to have the virus
professionally removed either by someone or to use their remote service for a fee of $149 which comes with several guarantees and does not require you to re-install software or documents. I hope that my response was of some help to you. I also kept trying
to fix this problem but wasted a lot of time. He also suggested to Google the proxy problem to see if ANYONE has any alternatives to fixing this problem!