PHP: Too many open links (0) with libpg7.4.3

Hi

I try to upgrade postgresql 7.3.3 to 7.4.3 on my machine running Apache
2.0.49 and PHP 4.3.7

Because i use another path for postgres 7.4 there (luckily) stay a old
libpg
So while i compile php with --with-pgsql=shared an old, 7.3.3 libpg is used
by PHP. Everything fine, run and works.

But specifing for php configure corect path --with-pgsql=path_to_new
postgresq , pglib 7.4.3 is used and result (after reboot ) is

Warning: pg_pconnect(): Cannot create new link. Too many open links (0) .

There was not a change of php.ini file and phpinfo() returns proper values ,
correctly find libpg7.4.3 and other properties. I even try to set
pgsql.max_links and pgsql.max_persistent from -1 (unlimited) to some
value without effect....

Where is a problem ?