It shouldn't be anything to do with day of the week (at least not directly).
There's no such error message (nor any other error message), and the clock in my room seems to work, but berry trees never grow (don't know about other time-based events, since the GBA games don't have day/night like the GBC ones). I tried it with sapphire, and the clock worked fine, berry trees started to grow within just a few hours. Tried emerald again, and still didn't work.