Get error after PHP4->5 migration

Hello,
last night my server updated PHP to version 5.2.9-1nmm1 and mysql to version 5.0.51a. This morning I had two problems.
1. I could not log in, most data from user 1 profile has been deleted ( password, etc ) -> fixed
2. I still have the error:
warning: array_merge() [function.array-merge]: Argument #2 is not an array in /www/htdocs/p1a992ms/includes/theme.inc on line 930.

from Line 929:

 if ($key) {
    $settings = array_merge($settings, variable_get(str_replace('/', '_', 'theme_'. $key .'_settings'), array()));
  }

How can I get rid of that message?