Random make check failures

I'm seeing random failures in the parallel tests run by
"make check". Sometimes (40% or so) all tests will succeed.
The rest of the time, I will get one or more failures.

The specific failures are connection failures:

! psql: connectDBStart() -- connect() failed: Connection refused
! Is the postmaster running locally
! and accepting connections on Unix socket '/tmp/.s.PGSQL.65432'?

I tried running pg_regress with --debug to see if it would
shed some light on the matter. I didn't see anything in the
output indicating what was failing on the backend.

I'm running on Solaris 8, with the 2nd update installed.

I'm new to postgresql, could someone with some experience give
me a few pointers on tracking this one down?

Steve Nicolai