This indicates a possible attempt to exploit a SQL Injection vulnerability in
Xmedien Anzeigenmarkt 2011.
The vulnerability, which is in "index.php", is a result of the application's failure to properly sanitize user supplied data.
Xmedien Anzeigenmarkt 2011
System Compromise: Execution of arbitrary SQL commands vulnerable systems.
Currently we are not aware of any officially supplied fix for this issue.