Ok this is for the new icq lite currently Build #1253. This will disable advertisment display but, unfortunatly will leave the place holders for the advertisments. Atleast you don't have to stare at those annoying flash advertisments.
1) Open up windows explorer and navigate to the folder you installed icqlite
2) Right-click on the folder and chose properties
3) In the properties dialog choose the security tab
*note: you may have to enable advanced security to view this tab on some versions of windows
4) In the security tab remove all permissions except for the system and set the system permissions to deny all access for read, write, etc.. for this folder
*note: you must have admin right to the machine in most cases and also may need to disable permission inhertince from parent under the advanced tab
5) Apply the changes and restart icq
What you have just done is denied Icq access to its temporary folder where it stores the advertisment information and now advertisments will not be displayed. This will work with any icq version as long as you can find the folder where it saves its advertisment info.