ItemError in DW in QueryMode

[yo yo]

Hi,

We are using DW in querymode as search box in our application.

When the User typed in field, it fills the Where clause and we display
him the result of his request.

It works, but when specific character are typed ( '_', '?', '/',...and
so more), event "itemerror" is triggered, and don't validate the
modification in the Where clause.

I haven't read some restrictions in the help, have you already met
this problem?

PB 11.2

Thanks in advance

Yoan