Customer can't search on Dynamic field

[napster]

Hi

I have OTRS 3.3.3 on Windows Server

I have several dynamic field (text, date,...) associated with tickets. I can search on dynamic field in interface agent but the customer can't search on any dynamic field. The result is
always : "no results found".

In log I've : [Mon May 19 13:50:14 2014][Error][Kernel::System::DynamicField::Backend::ValueValidate][722] Need UserID!
[Mon May 19 13:50:14 2014][Error][Kernel::System::TicketSearch::TicketSearch][1044] Search not executed due to invalid value '2014-03-01 00:00:00' on field 'ClosedTime'!

Thanks for your help !

and sorry for my bad english :/