Symbol.CreateMarker throwing a Null exception ?? was fine until updated to 1700

BrianLocke

 Dim LtBltSym1 As Symbol = Symbol.CreateMarker("\\nt\CFPA_PUBLIC\AGX\CustomIcons\ltning1.png")

this is throwing an exception when I try to create a mew symbol marker was working great until I updated the SDK to 1700 any suggestions??
Files are there are all strings are fine. Was working awesome until I updated the SDK????? ARGHGH >
NEED THIS ASAP!