Micromat Tech Support indicates that they have had similar problem reports recently. MacEKG should be performing its tests before any other software is loaded, including ARA.
The workaround is to rename the control panel "*MacEKG" to " MacEKG¬" (three spaces at the beginning of the name) and to move it from the Control Panels folder to the Extensions folder. This should ensure that MacEKG is indeed loading first. Once this is done MacEKG should no longer report that port B is being "touched", according to Micromat Tech Support.