intermittent regression check problems

Hello,

yesterday I reported an almost total failure in make check. As it was
suggested, I installed and then did "make check" again.

using that, I get a lower number of failures, around 20. I Still think
they are too much. Also the number is not stable, everytime I run it I
get a different result.

I past here two. I don't know how to itnerpret them. Maybe some errors
are expected in the regressions.diff file?
--- 404,409 ----
***************
*** 849,855 ****
ERROR: column "........pg.dropped.1........" of relation "test"
does not exist
copy test from stdin;
ERROR: extra data after last expected column
! CONTEXT: COPY test, line 1: "10 11 12"
select * from test;
b | c
---+---
--- 838,844 ----
ERROR: column "........pg.dropped.1........" of relation "test"
does not exist
copy test from stdin;
ERROR: extra data after last expected column
! lost synchronization with server, resetting connection
select * from test;
b | c
---+---

if I run make installcheck I get
============== dropping database "regression" ==============
dropdb: could not connect to database postgres: FATAL: role "multix"
does not exis

which is the user I am running from

Riccardo