I'm not very familiar with filter logic, but it appears there must just be an issue with the actual code. With all the data wires crossing each other, two of them may be connecting when you intended on to go over the other or vice versa.
Is there a reason you do not want to use the built-in LabVIEW VIs? Furthermore, the LabVIEW Adaptive Filter Toolkit has several tools that make filtering much easier (sorry, I don't mean to sound like a salesman..). If you're concerned with performance, these functions are typically as efficient - and sometimes more efficient - than hard coding everything.
Sorry I know this isn't terribly helpful, but I would recommend confirming that the logic is correct and/or trying to utilize some of LabVIEW's functions to make this a bit easier.
-Chris G
Applications Engineer
National Instruments