Error decrypting data

[sturner]

My problem is this 'ERROR DECRYPTING DATA' error shows when opening some 2004 format drawings. it is not every project but i have to do a recovery to open the drawing. the drawing will open fine in LDD 2006 and only give the error when opening in LDD 2009. is 2009 just more sensitive?? all drawings are existing projects located on our servers and service packs (i mean updates) have been applyed. is there a way to stop or surpress the error or is it just something we will need to work thru??
thanks,

Win XP
LDD 2006 & LDD 2009