On dec 31, 2012, FSYS's Account's payable balance was $42 million. Three months later, it stood at $51 million for a rise of 21%. That rise is a very good thing, as it implies the company's sales are rising at a brisk pace.
accounts payable is not necessarily a bad thing, as it can be for purchase of raw goods but it's short term debt that FSYS owes to vendors. your post is describing "accounts receivable"
That's looking on the bright side, as opposed to thinking maybe their customers aren't paying or paying as fast.