This post briefly discusses the new configuration auditing functionality to trace the changes done to the IIS configuration store. This is similar to the Metabase Auditing which was available in IIS 6.0 with SP1 on Windows 2003 Server; you can refer this KB article which talks about enabling metabase auditing on IIS 6.0 (with SP1).
In general, a 500.19 error happens due to invalid configuration data. The IIS configuration system will almost always point to the source of the problem. At the same time, sometimes it is important to examine the “Error Code” field which symbolizes the cause of problem.