Web Master:
Camellia cuttings are best taken from December to March, you can try at other times but may not be as successful. You don't mention when you took the cutting, how long they have been sitting under plastic or whether the final cutting is looking healthy. It can take up to 3 months for the roots to grow, longer over the winter. A good way of checking is to look for evidence of roots coming out of the base of pot. i would wait until you can see signs of roots and buds on the stem before taking it out of plastic bag. You want the soil to moist but not wet, too wet and you will encourage fungal disease and the cuttings will die. If the plant is enclosed in the bag it should need very little additional water, make sure the bag is not fully sealed as it is important for cuttings to get air.
Even the most experienced propagators have some deaths, so you should never expect a 100% success rate.