draggables don't work after upgrade from jquery UI 1.7.2 to 1.8

draggables don't work after upgrade from jquery UI 1.7.2 to 1.8

My draggables script was working great on jquery UI 1.7.2 with jquery 1.3.2, but after replacing the files with jquery-ui-1.8.custom.js and jquery 1.4.2, I get the following error:
 
    group[0].style is undefined:
 
(line 1594 jquery-ui-1.8.custom.js)
Any help would be much appreciated -- otherwise I can't use the new buttons in jquery 1.8 and will have to stay at jquery 1.7.2.  Is there an issue with backward compatibility
 
Thank you!