I've checked your JSON data
{'http://example.org/about': {'http://purl.org/dc/terms/title': [{'type': 'literal', 'value': "Anna's Homepage"}]}}
in http://jsonlint.com/ and the results were:
Error: Parse error on line 1:
{ 'http://example.org/
--^
Expecting 'STRING', '}', got 'undefined'
modifying it to the following string solve the JSON error:
{
"http://example.org/about": {
"http://purl.org/dc/terms/title": [{
"type": "literal",
"value": "Anna's Homepage"
}]
}
}