I love LED's myself, here is a few things to check. 1. Check what type of dimmer the bulbs need (yes you said you got a LED dimmer (Reverse phase dimming, used with most LED's, electronic transformers, and all dimmable CFL's), that will work with MOST led's but not all, some LED's are made for use with a standard incandescent dimmer (forward phase dimmer ((used with any led that has a magnetic transformer, or a product made for use with forward phase dimming)), so really it could be as simple as a switch.
2. Check the manufactures minimum circuit load raiting (do this for the bulbs and the dimmer) alot of LED's will flicker because there isnt enough resistance in the circuit. I.E your brand may need 6-10 6.5 watt led's for it to dim properly and not flicker when shut off (the dimmer itself should be ok with low load as thats what its made for, but may still have a min load), not having enough resistance in the circuit can cause flickering while on or intermittently while off. Just a few things to check, also a friend had a similar issue and bought a switch that required a neutral and the problem went away, I have only seen the problem once (I use both types of switches) and it was to little resistance.