I am attempting to put in a sample string to get my parsing right.
You are not using a string you are using a String. Not the same thing at all, but that does not seem to be the problem judging by the error message which seems to indicate that the problem lies with the underlying Java code behind the IDE.
It looks like you are going to have to take steps to reduce the size of the string. For instance does it need to be a full blown HTML table complete with details of background colours etc which will be irrelevant to the Arduino ?