Walt Whitlow was under treatment for cancer when he got an unwelcome surprise.  His financial assistance under President Barack Obama’s health care law got slashed.  That meant his premium quadrupled and his deductible went from $900 to $4,600.  Hundreds of thousands of people lose financial help and even their policies under the health law, because they get tangled in a web of paperwork problems involving income, citizenship and taxes.  Some are dealing with serious illnesses like cancer.  Advocates fear the problems are so extensive that if unresolved, they could undermine the nation’s historic gains in health insurance coverage.  The Obama administration says it’s working to make it easier for consumers to navigate the system and cut down on paperwork problems.