Answering to your first question:
May be your compute host doesn't have sufficient resources to provision a VM. just check your scheduler and compute logs as suggested by Umesh.
Answering to your second question :
I think their is some problem with your cinder configuration please check cinder.conf
Here I am providing the sample cinder.conf
[DEFAULT]
logdir = /var/log/cinder
state_path = /var/lib/cinder
lock_path = /var/lib/cinder/tmp
volumes_dir = /etc/cinder/volumes
iscsi_helper = tgtadm
sql_connection = postgresql://cinder:cinder@localhost/cinder
rootwrap_config = /etc/cinder/rootwrap.conf
api_paste_config = /etc/cinder/api-paste.ini
volume_name_template = volume-%s
volume_group = cinder-volumes
verbose = True
auth_strategy = keystone
iscsi_ip_address = < ip-addr >
[keystone_authtoken]
admin_tenant_name = %SERVICE_TENANT_NAME%
admin_user = %SERVICE_USER%
admin_password = %SERVICE_PASSWORD%
auth_host = 127.0.0.1
auth_port = 35357
auth_protocol = http
signing_dirname = /tmp/keystone-signing-cinder