Live Disk - boot up problems

Need some help here.  I am new to ubuntu - but have been using Knoppix for five years (another live linux cd).  I downloaded ubuntu this morning, burned a cd, and attempted to boot up into ubuntu.  CD in, turned computer on, and ubuntu started, selected language, and then selected to run ubuntu from the CD.  Screen goes blank and then I get two lines[67-009171] ACPI:EC: acpi_ec_wait time out, status = 0, expect event=1[67-009220] ACP:EC - read timeout, command = 128And that is all I get.  I tried 2 or 3 times before having to leave for work.Any ideas?  Burn a new CD, or is there some other issue?Thanks, kc