The Reporting inventory job should not throw an exception if one of a number of job chains is invalid

Current situation
The inventory jobs reads all configuration file in a given directory and performs several insert statements to the database. If a configuration is invalid (e.g. the job in a job chain includes the full path on the file system) it can happen that one of many configuration files can not be handled by the job. If this is the case, the job throws an exception after putting the statistic to the log.

Desired behaviour
Instead of an exception a warning should be written to the log. An exception should be thrown e.g. when the given directory is not accessable or the database connection is invalid.