Unfortunately there's no UI to setup the crowd connectino, so you'll have to do a bit of manual leg-work.
First off you need a crowd.properties file (i have ours in /etc/openfire) something like this:
application.name=<application name in Crowd>
application.password=<application password in Crowd>
application.login.url=https://<domain or IP address>:9091/
crowd.server.url=https://<domain or IP address>/crowd/
session.isauthenticated=session.isauthenticated
session.tokenkey=session.tokenkey
session.validationinterval=0
session.lastvalidation=session.lastvalidation
http.proxy.host=
http.proxy.port=
http.proxy.username=
http.proxy.password=
http.max.connections=20
http.socket.timeout=20000
http.timeout=5000
Then you need to set a couple of server parameters (e.g. through the UI)
admin.authorizedGroups = crowd-administrators (or whatever group you want to administer openfire)
provider.admin.className = org.jivesoftware.openfire.crowd.CrowdAdminProvider
provider.auth.className = org.jivesoftware.openfire.crowd.CrowdAuthProvider
provider.group.className = org.jivesoftware.openfire.crowd.CrowdGroupProvider
provider.user.className = org.jivesoftware.openfire.crowd.CrowdUserProvider
crowd.groups.cache.ttl.seconds = 3600
crowd.users.cache.ttl.seconds = 3600
In case you have self-signed certificates for openfire and/or crowd, add at least the first one of these two:
clearspace.certificate.verify = false
clearspace.certificate.verify.root = false
That should make those errors go away...
That's pretty much what i can tell i've setup specifically for getting openfire to work with Crowd (it happened over a period of time so i could have forgotten something 
Cheers,
Dennis