-In the Options dialog, the "Plot and Publish" tab, the Plot and Publish log file option

-In the Plot Stamp dialog (PLOTSTAMP), the Advanced button, the Log file option (PLOT.LOG)

-To switch off the plot logging automatically, add the following command to your AutoCAD startup sequence:

(command "_-PLOTSTAMP" "_LOG" "_NO" "PLOT.LOG" "")

http://www.cadforum.cz/cadforum_en/qaID.asp?tip=6199