Probably you did not read this. It solved all my problems. I guess is too late for you.
Firewire Audio Issues On Intel-based Mac Systems Running 10.4.11 & 10.5.4
If you've followed the standard troubleshooting procedure below for a clean install of the M-Audio FW drivers on 10.4.11 or 10.5.4 and you're still experiencing issues with your FireWire devices on your Intel-based Mac, please be sure that you're including the "model identifier" and FireWire chipset in your signature as outlined in this thread.
Model Identifier: APPLE MENU > ABOUT THIS MAC > MORE INFO > MODEL IDENTIFIER
FireWire chipset: Hold down "Command + S" on startup to boot your Mac into single user mode. The chipset info is listed next to OHCI FireWire and will be listed as TI [Texas Instruments], Lucent [Agere] or Agere.
You may also want to contact M-Audio technical support with this information.
If you purchased it in the US, simply submit an incident via our customer support portal
If you purchased it outside the US, please report the issue to your local distributor. You can find the appropriate contact information via our M-Audio Global Distributor Locater.
Try the following standard procedure for troubleshooting audio interfaces on Macintosh systems:
Before starting, disconnect all FireWire devices, including the M-Audio device, disable wireless & Bluetooth and repair your disk permissions.
Hard drive > Applications > Utilities Folder > Disk Utility
Choose Macintosh HD when the utility launches and click repair disk permissions on the First Aid Tab.
Zap your PRAM:
Hold down "Command + Option + P + R" while booting up the system. Continue holding this key combination until you here the start-up sound three times.
For more information on zapping the pram, please see this article.
Next, install the combo update of the version of OS X that you're running in order to update all of your system files. Please keep in mind that this is to ensure that there are no corrupted system files and it will not affect any of your personal files or any software that you have installed on your system; it will simply refresh your system files.
10.4.11 combo update
10.5.4 combo update
After installing the combo update, follow these steps to reinstall the M-Audio FireWire drivers* [Please follow them exactly]:
1. Repair disk permissions [again].
2. Uninstall the Specific M-Audio device driver using our latest driver download - Make sure that the device is disconnected.
3. Repair disk permissions.
4. Install the latest driver.
5. Repair disk permissions.
6. Shut down, connect your M-Audio device and restart. NEVER HOTPLUG YOUR FW AUDIO INTERFACE!
If you're connecting an M-Audio FireWire 410, 1814, Audiophile, Solo, Ozonic or ProFire Lighbridge, do NOT use the AC power adapter. If you're using the ProjectMix I/O, the NRV10 or ProFire 2626, the A/C power IS required.
Please test your M-Audio FireWire interface without any other FireWire devices connected, including any FireWire 800 devices. In addition, please leave your wireless and Bluetooth disabled for the test.
* NOTE: The "Family" drivers for the M-Audio FireWire 410, 1814, Audiophile, Solo, Ozonic, ProFire Lighbridge, ProjectMix I/O or the NRV10 CANNOT be installed on the same system as the ProFire 2626. Please use the latest FireWire Family to uninstall any previous installations of the Family drivers. Then, use the latest 2626 driver to remove any previous installations. Once both drivers have been removed, follow the standard troubleshooting for Mac outlined above.