If so you've come to the right place !
The fix is very simple, do the following :
- Open My Computer
- Open the C: drive
- Open the Program Files folder
- Open the Lavasoft folder
- Right click the Ad-Aware folder and chose properties at the bottom
- Click the middle tab at the top called security
- Place a check in the box for Full control
- Click ok
The cause of this issue is that when Ad-Aware installs it does not grant you full control rights over the folder the program and definition file live in.
So when you try to download an update Ad-Aware tries to modify the definition files and Windows does not allow this so Ad-Aware generates an error.
The irony of it all is that Ad-Aware is the cause of it's own error due to it improperly setting the permissions on the folder it lives in.