freebsd openldap server tls error

[Dave]

Hello,
    I'm setting up a FreeBSD openldap server for authentication. When i 
added in tls parameters, the TLSCACertificateFile, TLSKeyFile, and 
TLSCertificateFile now i am getting the below error. I've checked 
permissions on the keys and they are globally readable. Any suggestions?
Thanks.
Dave.

Jan 26 21:48:38 ldap slapd[43560]: main: TLS init def ctx failed: -1