Is that a windows server or linux? what version of php? What is the language setting? English? European or US date format?
I think the issue must have something to do with the default time format specified at: /webassist/kfm/initialize.php on line 93.
I found reference to this error at:
bug.php?id=49489
and it seems to be related.
Maybe try using:
$kfm->defaultSetting('time_format', '%H:%M:%S');
instead of:
$kfm->defaultSetting('time_format', '%T');
and you could try:
$kfm->defaultSetting('date_format', '%m/%d/%y');
instead of:
$kfm->defaultSetting('date_format', '%x');