Chances are your dimmers and bulbs just aren't compatible. There are at least four kinds of dimmers out there -- those labeled for incandescent only, those labeled for magnetic ballast, those labeled for electronic ballast, and universal.
These labels are typically wrong, of course (nothing's ever easy).
An incandescent-only dimmer is a leading-edge (forward) phase cut dimmer. It works by turning on the power partway into the sine wave, cutting off the rising edge. It requires only two wires (hot and load), and obtains power for its own use by using the low-resistance path through an incandescent filament when it is off. Generally works poorly if at all with an LED fixture.
An electronic ballast dimmer is a trailing-edge (reverse) phase cut dimmer, and works by turning the power OFF partway into the sine wave. It requires a neutral wire as well as hot and load. Originally intended for low-voltage halogen fixtures using an electronic ballast.
A magnetic ballast dimmer is also a leading-edge (forward) phase cut dimmer, but requires three wires. Originally intended for low-voltage halogen fixtures using a magnetic ballast.
A universal dimmer is a two-wire forward phase cut dimmer that is supposed to work well with both types of ballast, but in practice just sucks.
Your LED lights will likely dim properly with either an electronic ballast dimmer, or a magnetic ballast dimmer (even though the LED certainly uses an electronic ballast), but not both, and will work poorly or not at all with the other types. And of course if you have multiple brands of LED they could require different types.