Chrome App SecurityError on file creation

Question

I have the following code:

chrome.runtime.getPackageDirectoryEntry(function(directoryEntry) 
{
    directoryEntry.getFile("files/test.txt", {create: true, exclusive: false}, function(fileEntry) 
    {
        console.log(fileEntry);
    },
    function(error)
    {
        console.log(error);
    });
});

If the file does not exist and create is true I get an It was determined that certain files are unsafe for access within a Web application, or that too many calls are being made on file resources. error. But if it does exist and create is false I get access to the file.

What am I doing wrong?