Do you have something like these lines in your CfgAmmo section?
<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">hitGround[]={"soundHit1",0.330000,"soundHit2",0.330000,"soundHit3",0.330000};
hitBuilding[]={"soundHitBuilding1",0.500000,"soundHitBuilding2",0.500000};