Midipipe

I know this is listed as answered but reinstalling isn't the correct fix. When you hijack the MIDI port, it doesn't release by quitting MidiPipe.

Unplug your device from your computer.
Launch the app "Audio MIDI Setup" that is already on your Mac.
Open the MIDI window.
Select your device and delete it.
Plug in your device.

That should fix your problem without having to reinstall everything.

smoochdaddy09 wrote:
I used midipipe program on the inputs and hikacked the controller (61) and now I have no sound out of that keyboard.

Is seems to be a midi error which stacked you hardware controller. In some cases the hardware can not be reset just from a simple restart. That's why many hardware devices use special "Hardware Reset" - in most cases it is a combination of holding down some onboard button while you switch ON the Power supply button.
Cause I do not own the controller you have I did a little search and found out that:

+2.4.4 Reset+
+It is possible to completely reset your keyboard at any time. To do this, turn the Axiom off and then press and hold down both of+
+the -/+ buttons as you power up the keyboard.+
+Important Note: When you perform this reset, all of the factory presets are lost. To restore the factory presets, please use the+
+Enigma software, available as a free download at www.m-audio.com.+

!http://img59.imageshack.us/img59/4967/aglogo45.gif!

I came across this issue myself some time ago. What I found out was, that this seems to only occur on OSX 10.6.
On SnowLeopard, MidiPipe seems to have trouble releasing hijacked ports so you have to fix things manually by deleting and reinstating the respective device in Audio MIDI Setup.
However, on OSX 10.5 things work properly. Since PidiPipe is essential to my live rig, this was reason enough for me to revert back to 10.5.
Until there is an update to MidiPipe which fixes this issue, I won't touch SnowLeopard again. Very sad but true.

So quit/exit MIDIpipe, and it won't be doing anything.