It is most likely that you have corrupt audio files. Try selecting the audio files and consolidating them by pressing the key command: OPTION+SHIFT+3 (mac) or ALT+SHIFT+3 (windows). This will create a new audio file from your source audio file that may be corrupt. If this does not work, try making one of the tracks inactive.
Here is some potentially helpful information:
DAE error -9060 - a general list of potential causes on Mac OS and Windows.
1. Pro Tools does NOT support RAID arrays. This error can occur if drives are connected to a RAID SCSI controller, or if drives have been striped or formatted with a RAID formatting utility such as "Soft Raid".
2. Corrupt audio files can cause -9060 errors. In this scenario, the -9060 error message will come up in exactly the same spot in the session. A simple workaround is to set the track containing the corrupt audio to "inactive".
3. In one case, a bad Volume Bitmap on the audio drive was the cause (Disk Doctor reported "the contents of the bitmap do not agree with the locations of all files in the catalog"). Run a disk utility on the drive to check it. If an error is found, backup your data, initialize the drive, then restore your data.
4. In one case this was resolved by removing a Jaz drive from the SCSI bus.
5. Norton AntiVirus, Norton SystemWorks, and Virex have been reported to cause DAE -9060 errors on OSX. To remove them run the Norton uninstaller or remove the anti-virus files from Library>Startup Items.