Solved the problem with syntax expression, mentioned before. Instead of date and time it showed [d-m H:i]
Did you install a language pack? Dutch maybe?
Changes I made:
Admin CP> Languages & Phrases> Language Manager>Edit settings (of your installed language pack)>
First I didn't change any setting and pressed 'save'.
I message showed up, with something like "Could not find locale 'nl_NL' on the server"
pressed "go back' and cleared all fields in the section "Date / Time Formatting", pressed "save".
E whola... problem solved.
For detailed instructions see this link on Vbulletin.com forum (Language / Charset Problems - Things To Check) for instruction wich might help solve the problem:
http://www.vbulletin.com/forum/showthread.php?t=297299