if you are using the source code from codeproject as-is (at least as-is from the last time I checked it) there is a problem with NetMaster’s twCapability ctor. He assumes in his sample a static baseAddress size where he should have either calcualted the baseAddress size based on the ItemType or assumed a slightly larger baseAddress size. The result is that FIX32 types don’t work. It’s i nthe forumn comments on tha pag.