Give this a go and let me know how it works. If it created a sony/everquest folder at all in the previous failed attempts delete it.
Navigate to C:\Program Files\Common Files
Rename the folder called Installshield to Installshield_Old
Now try installing the Titanium disks again, if this doesn't work for you I think your next option would be to contact Sony's Tech support and give them the error message..
Good Luck
