What is the difference between CPM and eCPM, because I saw something in the Adbrite Setup about price to beat in eCPM.
CPM is a stable, always paying the same amount of money service. If You have CPM set at 0.75$ you will ALWAYS get 0.75$ per 1000 impressions. eCPM - estimated CPM - moslty is used for PPC networks - it tells You an average cost of 1000 impressions WITH clicks generated. Mostly eCPM are higher, but it is not guaranteed that You'll make that amount.
eCPM is effective cpm wich means is the real cpm, about the adbrite configuration i think you should rise it a bit , but AdBrite is not working for me :S.
eCPM is generally used as a statistic when payments are not based on impressions, or when the payments vary dynamically. The calculation is thousands of impressions/earnings.