There is no difference between using the standard IDE and the "enhanced". In actual fact, but I might not have observed that correctly, the standard IDE started to show this error a little earlier (meaning when my sketch was slightly smaller. In other words, when the error first appeared and I realised that replacing PSTR based commands into SRAM based onces, I checked with the normal IDE. The error appeared- and I think it did even with the version I had just "repaired" to work with the enhanced version. In any case, the error is with both.