False Sounds

I downloaded Every Breath You Take. The elec. guitar part is mostly 8th notes. The written score looks correct, but when I play it, it plays the first note of the riff as a 16th note and the second note as a dotted 8th note. Of course, it doesn't sound ANYTHING LIKE what the Dominic Miller composed. Very frustrating. If I change the first note (pitch) then it plays fine... How bizarre is that?? Can someone explain what's going on here. Thank you. (I paid my year's subscription today. So far I'm not impressed... luckily there's a whole year for me to change my mind about MS.)