Thanks for your patience and attention altef 4 and Razor12911 the problem was
Resolved (ExpandConstant ('{app} \') only modified thanks again to the next.
Code:
LabelCurrFileName.Caption:=ExpandConstant(' ')+MinimizePathName(ExpandConstant('{app}\ ')+CurrentFile, LabelCurrFileName.Font,WizardForm.FilenameLabel.Width);