Error on using a pager with views panes

Each of my panel pages which includes a views pane produces an error when any query string is found in the url.
This is not just happening with ?page=1 but also with any query string.

In the registry is recorded: "Recoverable fatal error: Argument 1 passed to drupal_http_build_query() must be an array, string given, called in /var/www/htdocs/ecogen1/html/sites/includes/common.inc on line 2271 and defined in drupal_http_build_query() (line 486 of /var/www/htdocs/ecogen1/html/sites/includes/common.inc)."

The panel pages path defines several arguments. Example: "/people/!term1/!term2/!string"
It makes no differences if they are all defined in the url or not.

Panel pages without placeholders in the path are NOT generating the error.

Any idea?