Thank you for the explanation, that makes really sense although I'd also like to link the recent images to the gallery where they are in (not showing a popup on the startpage). Event Calendar now works for me, the only problem I have is the German localization because wether the month names nor the headings of the filterform are translated. Do you have an idea where to look for those problems?

There was a small bug with the localisation that I fixed about a month ago. Do you know when you last updated your code?

I think May 6. It should be revision 105 or 106 (via svn).

Is everything else translated? The month names are generated using the PHP function strftime(), so if your PHP locale is not set to de_DE, then you probably wont' see the translations.

Okay, so now there are only a few strings that are not translated such aus "End" on the filter form or "show month" within the livecalendar_widget. Is it possible that they are not in the de_DE file?

So now I got nearly everything working by adding a custom LiveCalendarWidget.ss where I changed the text with language option:

before:
<optgroup label="<% _t('QUICKLINKS','Quick Links') %>" />
<option value="$QuickMonthLink">This month</option>
<option value="$QuickWeekLink">This week</option>
<option value="$QuickWeekendLink">This weekend</option>

after:
<optgroup label="<% _t('QUICKLINKS','Quick Links') %>" />
<option value="$QuickMonthLink"><% _t('THISMONTH','This month') %></option>
<option value="$QuickWeekLink"><% _t('THISWEEK','This week') %></option>
<option value="$QuickWeekendLink"><% _t('THISWEEKEND','This weekend') %></option>

I also added translations to my de_DE.php at /mysite/lang:
$lang['de_DE']['LiveCalendarWidget.ss']['JUMPTOMONTH'] = 'Direkt zu...';
$lang['de_DE']['LiveCalendarWidget.ss']['QUICKLINKS'] = 'Schnellzugriff';
$lang['de_DE']['LiveCalendarWidget.ss']['THISMONTH'] = 'Aktueller Monat';
$lang['de_DE']['LiveCalendarWidget.ss']['THISWEEK'] = 'Aktuelle Woche';
$lang['de_DE']['LiveCalendarWidget.ss']['THISWEEKEND'] = 'Aktuelles Wochenende';
$lang['de_DE']['LiveCalendarWidget.ss']['SHOWMONTH'] = 'Monat anzeigen';

At the end, I was also unable to find the Start and End text of the $CalendarFilterForm, "CalendarFilterFieldSet.START/END" ?