Not an expert and just trying to explain it in a positive way. Using L60 stones on a level 30 is overkill. Aion might be punishing you with fails for using too high enchant stones :). For Lvl 30 Gold/Fabled gear:
- L50 give 60% enchant chance
- L55 give 70% enchant chance
The intended way to handle this is use stones between L50-L55 and some kinah calculation to ensure you are getting best value for Kinah. There is an enchant calculator online that can help with this process.
Aion is an Eastern MMO. What this means is that things are not always explained/spoon-fed. You almost always need to do some research. For eg, I learnt this the hard way when leveling Alchemy. I burned through mats when I should have been doing work orders, leaving the mats for when the work orders run out. This was my mistake as I did not look into things.
Bottom line, always research things for Aion. Ask around, check forums. Although there are some frustrating things about Aion, most of them are just people (including me) doing things the wrong way.