leaking compression fittings on supply valves

This morning I discovered, unfortunately not until considerable water had collected, that the fitting downstream of the push-pull type supply valves to my dishwasher and sink hot water. Constant little dripping from this crimp, compression-type fitting, integral to the supply tubing. (Sorry, I don't know the correct terms.)

How do I fix this? Can I simply squeeze harder on these fittings? Do I have to buy new valves? (How are these attached to the copper supply lines?)

Many thanks in advance.

- Mark

Mark,

Could you take a digital picture and post it?
max size should be 400 pixels.

valve

They slide on and are held by "teeth" about the only way to remove them is to pull them while twisting them.