MinimizePathName error

[buttignol]

I wanted to add '"MinimizePathName" in my script but the error "The folder name is invalid" added only this to the sript

procedure InitializeWizard();
begin
with WizardForm do begin
DirEdit.text := MinimizePathName(WizardForm.DirEdit.Text,WizardForm.DirEdit.Font,WizardForm.DirEdit.Width);
ComponentsDiskSpaceLabel.Visible := false;
BorderStyle := bsSingle;
Center;
end;
WizardForm.DirEdit.Text := WizardForm.DirEdit.Text + #0;

Can someone help with what's missing Thank you