I have since the begin the xajax extension installed. In this extension the xajax.ini was stay in the install directory, so eZ search the DebugSettings of the xajax.ini but It dosn't find them because the file wasn't in the setting directory.
Sorry to hear you had some troubles with my xajax extension :-)
It probably would be better if eZINI reports the specific ini file which is missing a setting too. I'll post an issue for this: http://issues.ez.no/10315