When trying to create a release content pack (Release checkbox checked), I get this error:
Missing tag folder. Contact your SCM administrator
How can I resolve this?
As the error suggests, someone with Admin access to the SCM would need to perform this action, but it's basically looking for a 'tag' folder under the Project folder in your SCM. HPOO is incapable of creating it as needed.
In my experience, most people see this when using SVN (Git sets up tags in a different way) so I'm going to assume that that's what you are using. If that's accurate, the Admin should be able to run this command to create the Tags folder:
svn mkdir <path/to/project_repo>/tags
If you're looking for more details about Tags in SVN, you can check out this chapter from the SVN Book. http://svnbook.red-bean.com/en/1.7/svn.branchmerge.tags.html