Article ID: 5977, created on Jan 22, 2009, last review on Aug 12, 2014

  • Applies to:
  • Plesk 9.x for Linux/Unix


Installation or upgrade of Parallels Plesk Panel to version 9.x may fail on server based on CentOS 4.x with PostgreSQL 8.1.

Internal server error is shown on Parallels Plesk Contorl Panel:

500 - Internal Server Error

and the following messages appear in sw-cp-server error log.

/usr/bin/sw-engine-cgi: symbol lookup error: /usr/bin/sw-engine-cgi: undefined symbol: PQescapeByteaConn
2009-01-08 08:16:29: (mod_fastcgi.c.1004) the fastcgi-backend /usr/bin/sw-engine-cgi failed to start:
2009-01-08 08:16:29: (mod_fastcgi.c.1008) child exited with status 127 /usr/bin/sw-engine-cgi


NOTE: Since version 9.0 Parallels Plesk Panel CP server functions via sw-cp-server.

Note: If you are looking for a solution to the "500 - Internal Server Error", make sure you check out the main article: #114882:[HUB] 500 - Internal Server Error


Parallels Plesk Panel version 9.0 for CentOS 4.x is distributed with support of PostgreSQL 7.4.

If PostgreSQL 8.1 was installed from centosplus repository you should upgrade compat libraries as well. Libraries that come with Parallels Plesk Panel are outdated and may not load.
You may download the latest packages from

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