FOLLOW UP: I contacted Stereophile via e-mail through their website regarding the missing pages in the issue that I had received. They replied within 24 hours (not including their automatic response e-mail), letting me know that they are sending me out a new April issue at no charge.
Well, from all of your responses (thank you, BTW), it looks like this error is not widespread, but not unique either. Errors do happen in the retail business. I appreciate their customer service when there was a problem (isn't this when customer service really counts anyway?), and look forward to receiving my complete April issue.