looks like you are talking about one of the error messages from the webdev server, in which case they should be in the language of the webdev server, as it was installed (US or FR)...
if that is not the case, the help explains how to use your own page for that:
[doc.windev.com]
I had the same problem and I solved through the WB Administrator.
Select the "Advanced" tab and click the "Errors" button.
For some reason, several errors are still in French and you have to replace them by English.