PostgreSQL server 9.1.3 rejects connections after update: Error connection to the server: FATAL: frontend-protocol 1234.5887 not supported: server supports 1.0 through 3.0

Since the last PostgreSQL port update, server and client are version
9.1.3 and a newly build of the FreeBSD OS (both 9.0-STABLE and
10.0-CURRENT, amd64), clients like pgadmin3 or webinterfaces like those
from refdb reject connection to the PostgreSQL server with the error
message:

Error connection to the server: FATAL: frontend-protocol 1234.5887 not
supported: server supports 1.0 through 3.0

All users, execept a local admin and the psql user, are kept in
OpenLDAP. It seems, that the LDAP connection got messed up somehow.

I tried to recompile everything required by OpenLDAP, PostgreSQL via

portmaster -f, since I realized changes in Heimdal on FreeBSD 10.0-CUR
and I deleted the old libs via delete-old-libs/files.

Does anyone see this problem, too?

Regards,
Oliver