The excitement Aerosmith generated last week with its raucous street party on Commonwealth Avenue was short-lived. The New York Post reports that the band, which is embarked on the second leg of its “Global Warming” tour, is barely speaking to one another and, despite decent reviews, sales of the group’s new CD, “Music From Another Dimension!,” are lackluster. Of course, acrimony is nothing new to Steven Tyler, Joe Perry, Brad Whitford, Tom Hamilton, and Joey Kramer, who have had their share of highs and lows over the course of the band’s 40-year career. Their rep told the tabloid the band is having a fine time at the moment: “Aerosmith is doing great and on tour and on fire. Any claim to the contrary is absolutely false.” But it is true that the group’s new CD — its first set of original music in over a decade — is not selling as well as they may have hoped. We couldn’t reach anyone at Nielsen SoundScan, but word is the Aerosmith disc has sold less than Rod Stewart’s new “Merry Christmas, Baby” CD.