can you first try your ldap setup with the following command (try this directly on the perforce server)
- p4 ldap -t john.doe ldapconfigname
If everything is setup correctly then you should get a prompt to enter the users password, and after correct entry you should see a "Authentication succesful" message:
Discovered FullName: John Doe
Discovered Email: John.Doe@fluffycat.com
That would be a first step to debug the whole thing.