Hmm, strange indeed. What operating system and version are you running on? Since all of the versions fail there must be something that is not right that is not caught by tiki-check.
Can you locate your php error log (this would vary depending on your system) and see if there are any errors logged in there that might shed light on what's wrong? It might be the apache or webserver error log as well. If this is a Linux system it is usually in /var/log/..... (e.g. /var/log/apache2/error_log or something like that.
Are you low on disk space? (wild guess)