add GetStrings

stepmania/src/ThemeManager.cpp

@@ -178,8 +178,8 @@ try_element_again:
 			throw RageException( "Theme element '%s/%s' could not be found in '%s' or '%s'.", 
 				sAssetCategory.GetString(),
 				sFileName.GetString(), 
-				GetThemeDirFromName(m_sCurThemeName), 
-				GetThemeDirFromName(BASE_THEME_NAME) );
+				GetThemeDirFromName(m_sCurThemeName).GetString(), 
+				GetThemeDirFromName(BASE_THEME_NAME).GetString() );
 #ifdef _DEBUG
 		case IDIGNORE:
 			LOG->Warn(