Disconnect all peripherals from your computer.
Boot from your install disc & run Repair Disk from the utility menu. To use the Install Mac OS X disc, insert the disc, and restart your computer while holding down the C key as it starts up.
Select your language.
Once on the desktop, select Utility in the menu bar.
Select Disk Utility.
Select the disk or volume in the list of disks and volumes, and then click First Aid.
Click Repair Disk.
Restart your computer when done.
Repair permissions after you reach the desktop-http://support.apple.com/kb/HT2963 and restart your computer. Reinstallng Digital Performer 7.24 should now work. If not, you should contact its customer tech support department - http://www.motu.com/techsupport
Do you meet all of Digital Performer 7.24 system requirements?
Version 7.24
• Mac OS X 10.7 (Lion) compatibility
• Improvements and optimizations
Minimum System Requirements
Digital Performer 7.24 requires a computer with a 1 GHz G4 processor and 1 GB of RAM running Mac OS X v10.5.8 Leopard or later to install and run. A display resolution of 1024 x 768 is also required.
System Recommendations
The minimum recommended system for Digital Performer is a multi-core or multi-processor Power Mac G5 or Intel-based Mac with 2 GB of RAM or more. A display resolution of 1280 x 1024 is also recommended.
Pro Tools|HD System Requirements
Digital Performer supports DAE versions 8.0–8.0.3 with the following Digidesign Pro Tools systems:
• Pro Tools|HD (1, 2 or 3)
• Pro Tools|HD Accel
Pro Tools version 8.0 cs3 or later is strongly recommended. Support for Pro Tools 8.0.3 requires that Pro Tools is installed before installing Digital Performer 7.1 or later. If Pro Tools 8.0.3 is installed after Digital Performer 7.1 or later, the Digital Performer installer must be run again for DAE to function properly.
http://www.gfxtra.com/sof-mac/103753-digital-performer-724-updater-mac-osx.html
