[Zope] Problem adding ZClass after upgrade to 2.7

I just recently upgraded from 2.6 to 2.7 (running on Solaris). But now I can't add new ZClass objects anymore. I'm asked to login and then told I don't have permission. Copying, pasting, uploading new versions,etc of these objects is no problem. Any ideas on how to remedy this? TIA, Anthu