Try like this: 
AddCustomFieldValueByName('Title', TmpStr1 + '(' + TmpStr2 + ')');
This is how it should be in the script:
 //~mfTitle~ or ~Title~
 curPos := Pos('<title>', HTML) + Length('<title>');
 if Pos(') - ', HTML) > 0 then
	endPos := PosFrom(') - ', HTML, curPos)-6
 else
	endPos := PosFrom(' -  | ', HTML, curPos);
	TmpStr1 := Copy(HTML, curPos, endPos - curPos);
	AddFieldValue(mfTitle, TmpStr1);
	AddFieldValue(mfOrigTitle, TmpStr1);
		Title := Copy(HTML, curPos, endPos - curPos);
		Title1 := Copy(HTML, curPos, endPos - curPos);
 if Pos(') - ', HTML) > 0 then
	endPos := PosFrom(') - ', HTML, curPos)+1
 else
	endPos := PosFrom(' -  | ', HTML, curPos); 	
	TmpStr1 := Copy(HTML, curPos, endPos - curPos);
	//AddCustomFieldValueByName('Title', TmpStr1);
.
.
.
 //	~mfYear~ or ~Year~
 
 curPos := Pos('<span class="release-year">', HTML) + Length('<span class="release-year">');
 if Pos('</span>        </h2>', HTML) > 0 then
	endPos := PosFrom('</span>        </h2>', HTML, curPos);	
	TmpStr2 := Copy(HTML, curPos, endPos - curPos);
  if TmpStr2 = '0' then
	TmpStr2 := '';	
	TmpStr2 := StringReplace(TmpStr2, '(', '', True, True, True);
	TmpStr2 := StringReplace(TmpStr2, ')', '', True, True, True);
	AddFieldValue(mfYear, TmpStr2);
//	AddCustomFieldValueByName('Year', TmpStr2);
	
  if TmpStr2 = '' then
	TmpStr2 := 'year unknown';	
 LogMessage('	Parsing:	' + TmpStr1 + '(' + TmpStr2 + ')');
AddCustomFieldValueByName('Title', TmpStr1 + '(' + TmpStr2 + ')');
I did not tested, but it should work.