In a recent analysis of orbital data from the Mars Global Surveyor spacecraft, Iorio (2006 Class. Quantum Grav. 23 5451) found compelling evidence of general relativity's gravitomagnetic frame dragging effect. (A subsequent paper (Iorio L 2007 Preprint gr-qc/0701042v5) using the same data and equations claims agreement within 0.5% accuracy, exceeding that expected from NASA's Gravity Probe B.) However, this confirmation of general relativity was obtained by misinterpreting the MGS data and then altering a key time period.