Ensure that you have installed the WebUI Resources Package 
(opengroupware-webui-resource-[de|en]-latest.[rpm|dep] or /WebUI/Resources if u
got the source).<br />
In your OGo home directory (~opengroupware) there should be a Resource subdir 
containing language projects like like English.lproj or German.lproj.<br />
Therein the files OGoResourceScheduler.string and OGoScheduler.strings should
contain the missing labels.
<br /><br />
We just checked the packages from July, 21st. They seem to be alright.