Permission Problems after Migration

Question

I have been overcoming numerous problems following a FireWire migration of files from a PowerBook G4 running OS 10.4.11 to a MacBook Pro running OS 10.6.2. Nothing seemed to make the transfer seamlessly, but I have managed, after great effort and help from this community, to get the following migrated "correctly" (version changes in parentheses):
Address Book groups and cards (4.0.6 -> 5.0.1)
iCal calendars (2.0.5 -> 4.0.1)
Safari bookmarks (4.0.4 -> 4.0.3!)
Mail local folders (2.1.3 -> 4.2)
iTunes music (9.0.3 -> 9.0.3)
iPhoto pix (5.0.4 -> 8.1.1) - but "rolls" to "events" still needs work
The current problem is that a few of my files (so far, all password-protected Excel files) are Read-Only on my new machine. Not knowing that it might be an issue, I selected a different User Name on the new machine from the one used on the old machine. The machines are connected over the same network, and I have logged onto the old PB from the MBP successfully. Via Get Info, I have changed the permissions of these files from Read Only to Read and Write for Everyone, but I am still unable to save changes to these files. The Owner of these problem files is listed as the old computer's User Name. I doubt this is relevant, but I am also in the middle of changing from Office X to Office for Mac 2008. Using a tip from a MacWorld article of 3/28/08, I added the old User Name as an alias for the new User Name. This did not solve the problem.
I would truly appreciate any tips that would solve this problem quickly. I am extremely disappointed that the migration has proven to be such a painstaking exercise, one which is not yet complete.
Bob

Answer 1

Baltwo, your suggestion solved the problem easily. I gave in and restored the new machine to factory conditions and then migrated over FireWire seamlessly, with everything completely organized as expected. There was never any option to enter a new username; the old username was part of the migration. I no longer have any file permission issues.
I think the problem arose because I did not have a 9 pin FireWire cable when I started and attempted to migrate over the network - an option that was available. That did not work (due to permission problems!), but somehow I must have created a username on the new machine that ended up causing all of the problems.
Thanks again for pointing to the exact solution to my problem.