A LANDesk "Admin" will need to go into the User Management piece in LANDesk and add the "Software Dist." items to your "role"
I'm having this issue on an 8.8 SP3 server. Everything was working fine and then a couple of days ago Distribution Packages was missing from the Distribution menu all together. Myself and 3 others are all administrators and LDMS Administrators and all of us have this issue. Any help would be greatly appreciated.