I replaced an on/off switch with a timer switch. When the lights go on they blink on and off. Switch has 4 connections. Black wire, white wire, red wire, bare copper ground. There were two wires connected to the old switch and a ground. I removed the old wires and reconnected them as follows: White to bundled white at the back of the box, hot black from the box to black on the switch, neutral black from the box to red, ground from the box to ground on the switch.

Quote, "neutral black from the box to red". Don't know what that means?
White likely goes to white, Black likely goes to constant hot(whatever color), and the red is likely the load(whatever color) and is what connects to the light.
If these are CFL's, try regular bulbs?

Yeah, what's a neutral black? And are you using a CFL?

Sorry, the neutral black is really the switch leg. They are not CFL they are regular incandescent candelabra type bulbs. I think they're 40 watts.

Neutral is usually white or gray.
Never switch the neutral without switchng the hot.

Is this an electronic switch? Model number and make if possible.

Is this an electronic switch? Model number and make if possible.
It's a GE15071 electronic single pole switch

I have read where someone with this same switch used the white as a load wire and the lights flashed.
White needs to connect to the Neutral, Not all switchboxes have a Neutral, May be the problem, and the red is the load wire.
Double check which is your constant hot and hook to black.

Stratmando: This may be the problem but what do I do if I don't have a neutral? I only have two black wires coming out of the box. One is hot and the other is the switch leg.

Without the neutral the switch won't work properly. Are you wired with cable or individual wires in conduit?

I think its individual wires in conduit.

Without the neutral the switch won't work properly. Are you wired with cable or individual wires in conduit?

I think it's individual wires in conduit.

With power off, you may be able to push or pull a wire to a box that has a neutral.
It's a little odd to have a black and a white for a switch, if in conduit, unless they were wiring for a receptacle and later decided to make it a switch.
If pushing a wire, fold over 1/4" at the end and squeeze tight to eleminate the sharp edge of the wire.

Well if you are in conduit, those wires go to the light which has to have a neutral to work. Run a neutral wire from the light to the switch and you should be good to go.