Admin password required to proceed with upgrade?

I have installed a new 1.5.1. - my store is currently running 1.3.9
I saved a backup copy of my old database from 1.3.9
I imported the 1.3.9 DB into a the new database for 1.5.1 (phpMYAdmin)
I then attempted to upgrade the database using the zc_install
However, when I get to the upgrade page, I am asked for my Admin username & Password, so I enter the UN & PW I log into admin with, I click on the button to "UpDate Database Now", but the screen just comes back telling me Admin Password Required ...
The UN & PW are the same on both installs (1.3.9 & 1.5.1) so I am really confident that I am using the correct information.
I have a feeling that I am going to look really stupid here, because I cannot find any post of people having the same issue, but can anybody tell me what I am doing wrong?

Triple check your user & pass
The one for the 1.3.9 database

kobra:

Triple check your user & pass
The one for the 1.3.9 database

liam1964:

I have installed a new 1.5.1. - my store is currently running 1.3.9
I saved a backup copy of my old database from 1.3.9
I imported the 1.3.9 DB into a the new database for 1.5.1 (phpMYAdmin)
I then attempted to upgrade the database using the zc_install
However, when I get to the upgrade page, I am asked for my Admin username & Password, so I enter the UN & PW I log into admin with, I click on the button to "UpDate Database Now", but the screen just comes back telling me Admin Password Required ...
The UN & PW are the same on both installs (1.3.9 & 1.5.1) so I am really confident that I am using the correct information.
I have a feeling that I am going to look really stupid here, because I cannot find any post of people having the same issue, but can anybody tell me what I am doing wrong?
Should be the username and password you use to login to the store admin, not the database username/password..