I had to re-format my LaCie external hard drive where I had a volume with my Time Machine backups. Before reformatting I copied (by drag and drop) all the content of the folder "Backups.backupdb" on my desktop. To move back the content onto the externalo hard drive I did the following:

1. Fomatted the new volume as make sure to have a GUID partition and is formatted as Mac OS Extended (Journaled)
2. I dragged and dropped the content of the "Backups.backupdb" folder on my desktop onto the new TM partition on the external HD

These steps are somewhat similar to what suggested in an article I found on the apple support community "Mac OS X v10.6: How to transfer your backups from your current hard drive to a new hard drive" (Mac 101: Time Machine)

The size of the whole "Backups.backupdb" is approximately 150 GB and the partition for the TM is 500 GB. Nevertheless after indexing all the items in "Backups.backupdb" folder (during the prepare to copy phase) it says that there isn't enough space on the disk to copy the content. As additional note the indexing of all the items in the second copy/paste round (i.e. from the desktop to the newly formatted disk) took much longer than the indexing during the first round (i.e. from the disk to the desktop).

Can anyone help? What do I do wrong?
Thnaks a lot
P.S. I am running MacOS Lion.