On the textbox that you're doing that check if the Text Box Properties -> Number is set to Default, some computers give #Error when a given formatting is applied.
You can also try use CStr(Last(Fields!TAmount.Value)) and CStr(Last(Fields!TAmount.Value)) instead of the ToString.
You can also try to set the "& " in a Caption instead of raw text.
Or you do that filter in the C/AL side and return the string instead: FORMAT(TAmount,0,'<Precision,2><sign><Integer Thousand><Decimals,2>')
Answers
You can also try use CStr(Last(Fields!TAmount.Value)) and CStr(Last(Fields!TAmount.Value)) instead of the ToString.
You can also try to set the "& " in a Caption instead of raw text.
Or you do that filter in the C/AL side and return the string instead:
FORMAT(TAmount,0,'<Precision,2><sign><Integer Thousand><Decimals,2>')
Hope it helps, gl!