Programming PHP Sorry, too many clients already ....

Hi everybody !

We are developing a PHP-application with a postgresql-server, apache and
the php-module.

Developing works well until this day - a new developer entered out
team.
Now we are three developers:

No.1 Is developing on our main-server where the datatbase
      and the a webserver ist installed

No.2+3 are using the database on the Main-Server and have their own
        webservers on their machines !

Some People are also using these Webservers for testing !

Sometimes we got in our browsers the following Message:
--
Warning:  Unable to connect to PostgreSQL server:  Sorry, too many
clients already
  in
/var/www/html/ingeni/inc/class/st/boo/common/../../..//adodb/adodb-postgres.inc.php
on line 190
--

In this case reloading the page helps sometimes, but the best solution
is to restart the database.

What can be the cause for this problem ?

Our Components:

postgresql-7.1.2-4PGDG (on Redhat 6.2)
apache-1.3.19-5 (on Redhat 7.1)
apache-mod_ssl-1.3.12.2.6.4-0.6.0 (on Redhat 6.2)
     (Apache_Server with compiled in SSL-Support)

Regards

Marc Schöchlin