The most likely reason that you are getting this error is because the user that is running eclipse doesn't have write permission to the folder that is being used for the local media cache store.
If Wowza Streaming Engine then this will be /Library/WowzaStreamingEngine/mediacache. By default, the permissions for the /Library/WowzaStreamingEngine folder are read only for the regular users. You will need to reset these to allow write access.
If using the scripts to start Wowza normally then it runs as root user so you do see this problem.