Gilles, I think it's a VFP bug. I tried to use a parameterized statement like you did from the view designer and selected the IGNORE CASE button in the filter tab and got the same error you did. A quick fix is to put an ALLTRIM() around the field and parameterized variable and select the IGNORE CASE button. Example below works. Good Luck. :-)
SELECT *;
FROM ups_data!employee Employee;
WHERE UPPER(alltrim( Employee.last_name)) LIKE UPPER(alltrim(?lclname))
Michael Garcia