Another thing is that by default it is installed in single-user mode, this means that if one admin makes customizations to the tool, then other admin doesn't see these customizations.
Follow this steps to configure SCUP in multiple user mode:
1. Find the current location of SCUP database. You can do this by opening SCUP console, go to Options - Advanced, you will see location next to Database File.
2. Close the SCUP console and copy database file to another location. For example, D:\SCUPDB\scupdb.sdf
3. Go to C:\Program Files (x86)\System Center Updates Publisher 2011 and open file Scup2011.exe.config with Notepad
4. Append the text in bold in the file and save the file:
<setting name="SSCEDataFile" serializeAs="String">
5. Open the console, if you get an error, then give full control permissions to the SCUPDB folder directly to that user (not to group).