Jerry, You can not use thisform in a filter expression, for it goes out of scope, try building the filter with constants, something like
lcFilter = [UPPER(People.FName) = "] + ALLTRIM(UPPER(ThisForm.txtFName.Value)) + [" AND UPPER(People.LName) = "] + ALLTRIM(UPPER(ThisForm.txtLName.Value)) + ["]
set filter &lcFilter
Assuming there are no double quotes in the values of the text boxes
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